Asteroids and Bush Administration
Karol
With the new administration so much focused on defense systems and not
affraid of using nuclear devices and even weapons in space, would it
be possible to revive an old project Clementine 2? It was cancelled by
the Clinton Administration and was supposed to target some asteroids
to test technology for protecting our planet. Clemetine 1 was already
run by the Department of Defense and this one would not require an
increase in NASA budget either...
--
Karol
WebGuy
1.) All the terrorism - Is Bin Laden gonna hijack an asteroid? Not likely.
2.) Defense spending is the standard Conservative thing to do. But it only
includes defense from other humans, and that won't change unless our planet
is actually hit by something that kills a significant number of people.
Face it, the human race is mostly a pack of ignorant schmucks. They sit
there and pay 50% of their income to the federal government which dumps
billions of dollars into failing schools and lines the pockets of greedy
politicians of whichever of the 2 evil parties you subscribe to, and even
when Jupiter gets slammed by an impact which would have devastated or
destroyed our planet, many people don't even KNOW, and most that do only
have a vague idea of the implications, and generally just think "that will
never happen here."
What I don't understand is why interested people in the public don't start
organizing and funding private space missions. Screw NASA and the govt, it
will take them 2 centuries just to explore most of our solar system. We've
been in space for over half a century and still know almost nothing about
even our local neighbors. Sad, sad, sad.
Karol wrote in message <8b14c7a4.02032...@posting.google.com>...
Rod Mollise
>will take them 2 centuries just to explore most of our solar system.
Hi:
I'd add, "If EVER."
:-(
Peace,
Rod Mollise
Author of _Choosing and Using a Schmidt Cassegrain Telescope_
Like SCTs and MCTs?
Check-out sct-user, the mailing list for CAT fanciers!
Goto <http://members.aol.com/RMOLLISE/index.html>
life...@xxvol.com
>What I don't understand is why interested people in the public don't
>start organizing and funding private space missions.
What are the physics?
1. Given the recent asteroid that hid in the sun's glare, at what distance
could it be detected?
2. How big an asteroid would it take to pose a serious threat to Earth?
3. Given the difficulty of moving an extremely heavy object from its
trajectory, how much explosive power would it take to deflect it far
enough to miss Earth or to blast it to small enough bits to be of no
concern?
Jim L
Snip XX to Email
Chris L Peterson
>What are the physics?
>
>1. Given the recent asteroid that hid in the sun's glare, at what distance
>could it be detected?
That would depend entirely on the type and location of equipment being used for
detection. With space based detectors, the vast majority of objects large enough
to cause significant damage would be detectable at large enough distances to
allow for the possibility of intervention. In other words, the answer to this
question has more to do with politics and economics than it does with physics.
>2. How big an asteroid would it take to pose a serious threat to Earth?
An asteroid 10s of meters in diameter is approximately equivalent to a
thermonuclear bomb in terms of energy delivered. In the Gobi desert, little
serious threat, in central Europe, bad news. Objects of this size are common.
Get up into the range of 100s of meters, and you are now talking about large
damage over thousands of square miles, and worldwide ecological effects. Get
into 1000s of meters, and you are talking dinosaur killers, with profound
worldwide effects.
>3. Given the difficulty of moving an extremely heavy object from its
>trajectory, how much explosive power would it take to deflect it far
>enough to miss Earth or to blast it to small enough bits to be of no
>concern?
An explosion might not be the most effective way to get the job done. In any
case, it is a simple calculation to work out the energies necessary to deflect a
moving object. Obviously, this is something you want to do as early (and as far
away) as possible. Even for large objects, the energies involved are not beyond
our technical means.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
JMc
up. If you don't believe me, look at the glorious history of private
companies that attempted to compete with NASA - they are all gone. Take
a look at the paperwork and costs associated with launching a satellite.
You need approvals from NASA, DoD, FAA, FCC, EPA, and DoC, and most will
insist on detailed mission assessments and analyses before acting.
As long as it exists, NASA will NEVER allow private access to space. The
best bet would be to enlist help from a small island nation near the
equator.
Jim McSheehy
> WebGuy wrote:
> What I don't understand is why interested people in the public don't start
> organizing and funding private space missions. Screw NASA and the govt, it
> will take them 2 centuries just to explore most of our solar system. z
Jonathan TATE
You will find your answers there.
J Tate
The Spaceguard Centre
<life...@XXvol.com> wrote in message
news:3c9f5fc6$1$yvsrqngn$mr2...@news.vol.com...
life...@xxvol.com
>On Mon, 25 Mar 2002 12:25:26 -0500, life...@XXvol.com wrote:
>>What are the physics?
>would be detectable at large enough distances to allow for the
>possibility of intervention.
That doesn't sound much like a physics reply. "Enough distance?"
"Possible intervention?" Enough defines nothing. Possible? If you're
going to save the world you have to come up with a better tool than
something that might possibly work.
>In other words, the answer to this question has more to do with
>politics and economics than it does with physics.
You suggested it be done privately. That has nothing to do with politics.
It has everything to do with the physics of getting the job done. To
phrase it another way, what would this theoretical private concern have to
do in order to save the world?
>An asteroid 10s of meters in diameter
Can this private world protecting organization depend on an asteroid being
that small?
>is approximately equivalent to a thermonuclear bomb
A thermonuclear bomb? What kind? What size? The physics, man. The
physics. What does it take to do the job?
>An explosion might not be the most effective way to get the job done. In
OK, so we're talking about flying out there and attaching a big rocket
engine to it and pushing a 5000 meter chunk of rock or iron (let's assume
the worst) off course.
>any case, it is a simple calculation to work out the energies necessary
>to deflect a moving object.
All right, use a Saturn engine with its specific maximum burn time for
example. How many Saturn engines would it take to push our newfound 5000
meter chunk of iron off course? Then, how many Saturn engines and much
money would it cost to get that many Saturn engines off the ground, into
planetary orbit and alongside this little doodad that's about to destroy
us?
>Even for large objects, the energies involved are not beyond
>our technical means.
How about our time constraints and how about the private corporation's
fund raising ability? Politics aside, of course?
life...@xxvol.com
>You will find your answers there.
I'm not sure their proposed "gentle nudge" is going to get the job done in
a worst case scenario.
Tim Walker
> 3. Given the difficulty of moving an extremely heavy object from its
> trajectory, how much explosive power would it take to deflect it far
> enough to miss Earth or to blast it to small enough bits to be of no
> concern?
>
Well that depends on how far away we detect the object. The further away
the easier it would be (less power required) to defelect. Of course
deflecting an object we find four days _after_ it goes past us would
require a break with einstein :)
Tim
Joe Hotchkiss
Planet Earth" at
http://www.fas.org/spp/military/docops/usaf/2025/index.html
The report was prepared in 1996 for the USAF Chief of Staff and
Secretary of the Air Force, so presumably some serious thought went into
it.
This table from that report is of energy required to deflect an asteroid
(first and second rows) or destroy an asteroid, at a time when the
asteroid is greater than two week's distance from earth (I think).
------------------------------------
Nuclear Charges Required for Various Asteroid Employment Scenarios
Asteroid 0.1 km 1 km 10 km
Size
Proximal 0.1-1 kt 100 kt-1 mt 100 mt-1 gt
Burst (with
radiative
efficiency of
0.3-0.03)
Surface 500 kg 90 kt 200 mt
(with radiative
nuclear charges)
Subsurface 800 kg 22 kt 0.6 gt
(optimally buried
charges)
Subsurface - 1 kt 1 mt 1 gt
soft rock
(optimally buried
charges)
Subsurface - 3 kt 3 mt 3 gt
hard rock
(optimally buried
charges)
------------------------------------
Yield Versus Mass for Nuclear Explosive Devices
Yield Mass
1 mt 0.5 ton
10 mt 3- 4 ton
100 mt 20- 25 ton
1000 mt (1 gt) 120-150 ton
------------------------------------
--
Joe
http://joe.hotchkiss.com
Chris L Peterson
>That doesn't sound much like a physics reply...
I didn't invest a lot of time with the numbers because even the simplest
calculations show that the kind of forces needed to deflect threatening objects
at detectable distances are in the same range as forces we now can deal with. My
point was simply that the limiting factors are primarily political and economic,
not technological.
Just a BOTE calculation:
Assume: (1) we detect a 10km diameter asteroid at a distance of 2.5AU (this is
about equivalent to seeing a Martian moon); (2) its velocity is towards the
Earth at 20 km/s; the object has a mass of 1E15 kg; we want to deflect it by 5
Earth radii; by the time we intercept, there are 100 days left before collision.
To get the needed deflection, you need to apply a constant force of around 1E9
newtons. Over the deflection distance, that works out to around 1E16 joules, or
2 megatons TNT.
Frankly, that sounds very doable, especially given the ramifications of failure.
Obviously, it can't be done without a system already in place, though. If we
detected such an asteroid tomorrow, I don't see how we could possibly do
anything about it.
>You suggested it be done privately...
Hey, I never suggested that asteroid deflection be left to a private firm. IMO,
that would be silly, and make no economic sense at all.
>>An asteroid 10s of meters in diameter
>
>Can this private world protecting organization depend on an asteroid being
>that small?
You have to design the system to work within some size range. Asteroids this
size hit every few centuries, maybe more often. That is a much more immediate
threat, and much easier to deal with. The point is, politics and risk assessment
determine the maximum size object we choose to protect ourselves against. My
feeling is that we currently have the technology to protect ourselves from
objects as small as ~10 m, and as large as ~10 km. Smaller, and detection
becomes the limit, larger and deflection becomes a problem.
>A thermonuclear bomb? What kind? What size? The physics, man. The
>physics. What does it take to do the job?
We are just throwing around approximate energies, and in that sense, all
thermonuclear bombs are the same- 10s of megatons TNT?
>OK, so we're talking about flying out there and attaching a big rocket
>engine to it and pushing a 5000 meter chunk of rock or iron (let's assume
>the worst) off course...
I would think that if we used some type of engine, it would not be chemical. It
makes no sense to take all that fuel all the way to interception. Maybe some
kind of ion drive, using the asteroid's matter? Then all you would need to take
would be the energy, maybe a nuclear reactor. That sounds much more practical.
Or maybe you just nudge it with multiple nuclear explosions. Again, this sounds
like a practical engineering problem, not something limited by either our
technology, or worse, by physical constraints.
WebGuy
defense system should be privately run and funded, sorry if that was
implied. I meant general space exploration, which is currently progressing
at a pathetically slow rate.
WebGuy
what you are basically saying is "don't even try to stop the ones we could
have stopped cause there will always be one we can't stop!" So, just shut
your defeatist pie-hole.
life...@XXvol.com wrote in message
<3c9f9ba3$4$yvsrqngn$mr2...@news.vol.com>...
Karol
> Because NASA controls access to space, and they aren't going to give it
> up. If you don't believe me, look at the glorious history of private
> companies that attempted to compete with NASA - they are all gone. Take
> a look at the paperwork and costs associated with launching a satellite.
> You need approvals from NASA, DoD, FAA, FCC, EPA, and DoC, and most will
> insist on detailed mission assessments and analyses before acting.
>
> As long as it exists, NASA will NEVER allow private access to space. The
> best bet would be to enlist help from a small island nation near the
> equator.
Clementine 2 already WAS approved by DoD and it was actually a
MILITARY project. There must have been some early development prior to
cancellation and my question is how much work had already been done
and would it be possible to revive it. It was not actually a planetary
defense project, just a little excercise to see how it would be like
to shoot at asteroids. I would also like to know what type of weapons
was Clementine 2 supposed to be equipped with and a list of
preliminary targets since this information is hard to find.
--
Karol
JMc
FAS is a fairly good site for this kind of stuff.
Jim McSheehy
Tim Walker
anyone know the kind of charges they buried in armagedon? :)
Tim
Orion
While I like the idea of "public organizing and funding private space
missions"
I really think that if such a campaign were to get serious legs, the
gum'mint would crush
such a program into dust. The Feds have one agenda, and one only, and that
is absolute power, and they will never give that up, except by force....Your
point:
"the human race is mostly a pack of ignorant schmucks" is especially true
when it comes to political reality, and in the USA, the sheeple are as dumb
as dirt....Think about it for a minute,,,, the Fed's have info that is STILL
classified going back as far as WW1 and probably farther than that...Info on
the JFK assassination that is locked down until 2039..What possible reason
for such secrecy can there be, except to cover up crimes, atrocities, and
God knows what else?...Whatever it is, you can bet your bottom dollar it's
not good...Until the people of this country hold it's leaders feet to the
fire, and DEMAND accountability( which will happen on the 12th of never),
the idea that the sheep are going to be allowed to go into space will remain
a dream. The reason "conspiracies" never happen in this country is because
the government says so, and the media lapdogs are all too happy to support
that dogma...Every day we wake up, we have less and less freedom, you go
outside, and by the end of the day, you've broken dozens of laws that you
don't even know about... The INS fiascoes are a fine case in point. By any
reasonable definition, there're conduct is , at best, criminally negligent,
and yet , not one single person has been fired, nor can they be, nor will
they be.....You say, "but wait, we can VOTE!" Yeah, and when you have 2
wolves and a sheep at the table voting on what to have for dinner,it's a
forgone conclusion what the outcome will be....I love my country, but the US
government scares me far more than any terrorist....BTW, I do not consider a
handful of filthy rich dilettante's going into LEO, as a bonifide example of
a "private" space tourism..Secrecy will, ultimately, be the downfall for
this country...
Food for thought....
Orion
"WebGuy" <web...@pghmail.com> wrote in message
news:3c9efe46$1...@news.pghmail.com...
Thad Floryan
| [...]
| What I don't understand is why interested people in the public don't start
| organizing and funding private space missions. Screw NASA and the govt, it
| will take them 2 centuries just to explore most of our solar system. We've
| been in space for over half a century and still know almost nothing about
| even our local neighbors. Sad, sad, sad.
Re: "... funding private space missions", I doubt even the combined
resources of, say, Bill Gates (Microsoft) and Larry Ellison (Oracle)
could get such a project off the ground (no pun :-) today.
There's no lack of interest, just lack of money and time.
FOr example, around 1975 a neighbor, Bob Truax (the guy wwho designed and
built Evel Knievel's rocket motorcycle), started "Project Private Enterprise"
and actually successfully test-fired (on static mounts) several of his new
designs of a manned spacecraft. This was featured in OMNI and all the local
(SF Bay Area) newspapers. I still have a copy of his prospectus because I
was seriously interested in investing.
Bottom line, though, concerned innumerable regulatory obstacles and, of
course, funding. Such projects seem like a fiscal black hole for years
and it'd take decades for any significant ROI.
Governments are the only entities [today] with the longevity and resources
to support and continue space research.
John Savard
wrote, in part:
>What I don't understand is why interested people in the public don't start
>organizing and funding private space missions.
Tragedy of the commons.
People have a little money they're willing to give away, and that goes
to things like Oxfam, Unicef, the American Cancer Society, and their
local PBS affiliate. Something like September 11 will get them to dig
a little deeper.
But in general, people are pretty busy scrambling to make enough money
to do things like:
- buy a car
- take a girl out on a date to nice places
- buy a house in the suburbs that gives one's children a nice place to
play, and safe schools to attend
- send one's children to college, so they can get jobs that pay enough
to support a family
and technology doesn't seem to have made it any easier to do these
things. At first glance, this seems odd, but there are reasons for
this.
Think of all the women who were sexually abused and don't want
anything to do with men any more. Think of the women who got pregnant
in high school, and kept the baby even though their boyfriends weren't
ready for a commitment and ran away, and who now live their lives
centered around their child and don't really have time to look for a
new man, if one would accept, or be trusted with, the responsibility
of helping to look after a child not his own. Think of the second and
third young wives of some rich men. Think of women who are wealthy,
and weigh 300 pounds, and remember that a boy toy is a far more
dangerous and unpredictable pet than a Rottweiler.
Total up all those women, and you'll find there aren't enough gay men
to balance them out.
That's why economic competition is staying at the tooth and claw
level. Not because we'll all be happy once we get holographic 3-D
television sets.
So it is *way* easier to get people to *vote* for using tax money for
asteroid defense and sending people to Mars, because that way everyone
will pay their share, than for people to support a common good at the
expense of their own ordering in this intense competition.
John Savard
http://members.shaw.ca/quadibloc/index.html
WebGuy
behind the government's back... once it's launched what the hell are they
gonna do? Oh well.
Orion wrote in message ...
WebGuy
>resources of, say, Bill Gates (Microsoft) and Larry Ellison (Oracle)
>could get such a project off the ground (no pun :-) today.
Ummm I thought for instance the recent Mars missions only cost several
hundred million each? That isn't too much money for someone like Bill Gates
if he was actually interested in doing it.
WebGuy
I hate cars and I think public transit is the way to go personally.
Unfortunately you still need a car for a lot of things.
>- take a girl out on a date to nice places
I am against this also. :)
>- buy a house in the suburbs that gives one's children a nice place to
>play, and safe schools to attend
>
>- send one's children to college, so they can get jobs that pay enough
>to support a family
>
>and technology doesn't seem to have made it any easier to do these
>things. At first glance, this seems odd, but there are reasons for
>this.
>
>Think of all the women who were sexually abused and don't want
>anything to do with men any more. Think of the women who got pregnant
>in high school, and kept the baby even though their boyfriends weren't
>ready for a commitment and ran away, and who now live their lives
>centered around their child and don't really have time to look for a
>new man, if one would accept, or be trusted with, the responsibility
>of helping to look after a child not his own. Think of the second and
>third young wives of some rich men. Think of women who are wealthy,
>and weigh 300 pounds, and remember that a boy toy is a far more
>dangerous and unpredictable pet than a Rottweiler.
How the hell did this get women-centric? I don't get where you are going
with this unless you are implying that there is some kind of
eligible-woman-shortage which causes the men to have to make lots of money
to try to get one? I don't buy it. Are you lonely and thus developed this
theory to explain why you don't have a woman? No offense dude, I don't have
one either, but they are much easier to explain, believe me. It's all
animal behavior.
>Total up all those women, and you'll find there aren't enough gay men
>to balance them out.
>
>That's why economic competition is staying at the tooth and claw
>level. Not because we'll all be happy once we get holographic 3-D
>television sets.
>
>So it is *way* easier to get people to *vote* for using tax money for
>asteroid defense and sending people to Mars, because that way everyone
>will pay their share, than for people to support a common good at the
>expense of their own ordering in this intense competition.
No it isn't, because as you said the majority of the people don't give a
rat's ass what lies beneath the crust of Europa, or even know that Europa
exists. All it takes is a few whining Democrats in there saying how if
there were just a few more billion dollars dumped into education, or
welfare, or whatever, it would fix itself and all the heartless Republicans
are wasting your money on "tax cuts for the rich" etc etc. Not that the
Republicans are much better. I don't belong to either party, I find the
whole system revolting. So let's tear down the supercollider, who cares
about advancing science, let's scrap most of the space missions, we can send
one probe out every 10 years on a shoestring budget so that it's
super-widget can fail and send it hurtling into a rock somewhere, so they
can clamor even more how useless it is to "throw money away" on space
projects.
I guess the eye-opener is remembering that we never went into space for
scientific or noble reasons, we did it to compete with communist Russia.
Now that the "allied" world no longer has an enemy on its technological
level, we will have nothing but complacency. Maybe it's better off that
Bill Clinton and the rest of the corrupt leaders in both parties sold our
technology to China for campaign money, if they become a technological
threat maybe we'll start advancing science again.
Marty
Marty
Sjoplinh
post), but then went off on his own:
>>All it takes is a few whining Democrats in there saying how if
there were just a few more billion dollars dumped into education, or
welfare, or whatever<<
He whined about Clinton in particular, as well.
I'd say this: All it takes is a bunch of goofy Republicons whining about
"Iraq" ( while they let Pakistan / Musharraf off scot-free, as well as the war
criminal Sharon) and "missile defense" to put a huge kibosh on any scientific
space program...
sj
WebGuy
Sjoplinh wrote in message <20020326193612...@mb-fl.aol.com>...
>WebGuy complained about John S's post getting "woman - centric" (it WAS a
weird
>post), but then went off on his own:
>
>>>All it takes is a few whining Democrats in there saying how if
>there were just a few more billion dollars dumped into education, or
>welfare, or whatever<<
>
>He whined about Clinton in particular, as well.
If you would learn to read (clear thinking is a hard thing for a loyalist
liberal to do, I know) you would have noticed the multiple times where I
said I dislike the republicans also and don't belong to either of the 2
corrupt evil parties. Take your partisan diatribe somewhere else.
Karol
> I thought President Carter was the one that had asteroids...
Thanks Marty, now we are getting back to the main question. I thought
we would be more specific instead of discussing some drifted-away
sub-topics. Anyway, here is some food for your thoughts:
"27 October 1997
NEWS RELEASE:
National Space Society Statement On President Clinton's Line Item Veto
Of Military Space Programs
CONTACT: Karen Rugg, 202-543-1900
Washington, DC -- The National Space Society today issued the
following statement regarding the October 14 presidential line item
veto of military space programs.
The National Space Society was disappointed to learn of President
Clinton's recent line-item vetoes of several small military space
programs.
The Clementine 2 asteroid intercept mission, as with Clementine 1,
would have been the most cost-effective approach to combining
important technology demonstrations with real scientific missions.
Data on the mechanical strength of asteroid Toutatis would have
provided vital input to the construction of weapons capable of
deflecting asteroids or comets on a collision course with Earth. The
threat of worldwide devastation from this kind of impact should very
much be a Department of Defense (DoD) concern.
The line-item veto also cancelled funding for the military space
plane. While the National Space Society cannot address the merits of
any missions for which the space plane might have been used, we do
recognize the ability of the DoD's project to address a specific
combination of needs related to lowering the cost to access space.
Even though NASA is developing space plane-related technology, this
combination -- global range, extremely fast response, very low cost
per flight, and small support and ops crews -- cannot be addressed by
current NASA, commercial technology or development programs.
The National Space Society encourages the Congress, the Administration
and the DoD to re-examine the status of these vetoed programs, in
particular Clementine 2, in order to identify options to reinstate
funding."
So, what do you think? As you can see, they WANT to revive the
project. Is Clementine 2 worth sending a petition to the Bush
Administration? How about that?
--
Karol
DSmith2773
me. Actually, I already knew the answer.
A friend at work heard a good ole boy on a talk radio station saying that the
great light he saw in the sky turned out to be an asteroid that the gov. had
blown up!!!
My friend asked was this possible. I told him no, that many astromnomers were
reccomending that the gov. set up such a system before the 'big one' comes.
Just in case I had missed such a world newsworthy event, I searched the goup
for any signs that this 'may' have happened, and, of course, there were none.
Where do people come up with these things?
David from Chattanooga Tennessee, home of the Redneck Asteroid Buster's.
Karol
> I wanted to ask a question, but reading this thread has already answered it for
> me. Actually, I already knew the answer.
>
> A friend at work heard a good ole boy on a talk radio station saying that the
> great light he saw in the sky turned out to be an asteroid that the gov. had
> blown up!!!
>
> My friend asked was this possible. I told him no, that many astromnomers were
> reccomending that the gov. set up such a system before the 'big one' comes.
>
> Just in case I had missed such a world newsworthy event, I searched the goup
> for any signs that this 'may' have happened, and, of course, there were none.
>
> Where do people come up with these things?
Dear David, I really do not understand why do you think Clementine 2
was such a bad idea? It could be the first step towards a planetary
defense system. I am not a Republican, I am not even a US citizen and
I strongly criticise Republicans elsewhere, but I really think we
could use the situation and revive the project that could save lives.
Is that something wrong?
--
Karol
Bob May
>
> David from Chattanooga Tennessee, home of the Redneck
> Asteroid Buster's
all the answers that they will lie about things? Ask one of them some
really stupid question and I'll bet that he'll have an answer that sorrt of
makes sense on some level that is totally wrong. They're basically just
lying to get the recognition of being a poobah - something that they aren't.
--
Bob May
Imagine the terrorist's fun when they realize that their 72 "nubile virgins"
are all lesbians and cranky from it being that time of the month!
Sjoplinh
was such a bad idea? It could be the first step towards a planetary
defense system. I am not a Republican, I am not even a US citizen and
I strongly criticise Republicans elsewhere, but I really think we
could use the situation and revive the project that could save lives.
Is that something wrong?
--
Karol<<
One of many worries is that it might not be used for defense per se.
Even now the US' definition of "terrorist" is very selective. We're giving
full support to war criminals like Sharon.
sj
JOHN PAZMINO
D > Date: 29 Mar 2002 00:50:59 GMT
D > Organization: AOL http://www.aol.com
D > Subject: RE: Asteroids and Bush Administration
D >
D > I wanted to ask a question, but reading this thread has already answered it for
D > me. Actually, I already knew the answer.
D >
D > A friend at work heard a good ole boy on a talk radio station saying that the
D > great light he saw in the sky turned out to be an asteroid that the gov. had
D > blown up!!!
D >
D > My friend asked was this possible. I told him no, that many astromnomers were
D > reccomending that the gov. set up such a system before the 'big one' comes.
D >
D > Just in case I had missed such a world newsworthy event, I searched the goup
D > for any signs that this 'may' have happened, and, of course, there were none.
D >
D > Where do people come up with these things?
D >
D > David from Chattanooga Tennessee, home of the Redneck Asteroid Buster's.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Can you really be asking?
---
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Thad Floryan
You're neglecting the fact NASA et al already has a tracking and mission
control infracture in place. To begin from scratch would cost billions.
Just to give a hint of some of the costs involved, about 10 years ago a
friend, Monte Zweben, and his team at NASA-Ames used AI techniques to
develop a series of procedures to reduce the costs and turnaround time
of refurbishing each USA Space Shuttle, for an approximate savings of
$50 Million per mission. For their efforts they were awarded the highest
NASA Space Prize and used the award money to found a company, Red Pepper
Software, to transfer that technology to the commercial sector (e.g. for
airlines, etc.)
Manned space launches will remain costly for the foreseeable future unless
someone can capitalize and bring to fruition some of the research done at
Rensselaer Polytechnic Institute (in Troy NY) on a vehicle which, given its
shape with the application of a high-power laser, would ignite the atmosphere
as fuel along its skin creating a plasma and levitate, with the hopes the
technique could/would be eventually used as a ground-to-space vehicle. If
anything could look like a "UFO" that was definitely it.
Karol
> "WebGuy" <web...@pghmail.com> wrote:
> | >Re: "... funding private space missions", I doubt even the combined
> | >resources of, say, Bill Gates (Microsoft) and Larry Ellison (Oracle)
> | >could get such a project off the ground (no pun :-) today.
> |
> | Ummm I thought for instance the recent Mars missions only cost several
> | hundred million each? That isn't too much money for someone like Bill Gates
> | if he was actually interested in doing it.
>
> You're neglecting the fact NASA et al already has a tracking and mission
> control infracture in place. To begin from scratch would cost billions.
NASA is already there, DoD is already there and Clementine 2 project
is waiting to become reality. If we could develop effective unmanned
means of deflecting asteroids by just a little practice at the
beginning it might be worth to reconsider it. Bush Ad is going to pump
lots of money into military space projects anyway, so why don't we
take a piece of the action for the astro world?
--
Karol
Thad Floryan
I agree wholeheartedly!
My comments about costs pertain to the article which began this thread
asking about the economics and feasibility of a "private" space program.
Hmmm, just noticed I also typo'd "infrastructure" as "infracture"; the ol'
keyboard is too slow. :-)
Karol
> I agree wholeheartedly!
>
> My comments about costs pertain to the article which began this thread
> asking about the economics and feasibility of a "private" space program.
>
> Hmmm, just noticed I also typo'd "infrastructure" as "infracture"; the ol'
> keyboard is too slow. :-)
Dear Thad, it was ME who started the thread and I ask from the
beginning whether we should take some action to revive the Clementine
2 project. After some people who thought I am a Republican and others
who maybe thought I am trying to kook in here, finally I am beginning
to receive some decent response. So, should we ask DoD to shoot at
Toutatis with Clementine 2 and later start building our planetary
defense system or not?
--
Karol
Thad Floryan
As I previously wrote, I agree those programs should be funded and developed.
Anyone opposing such programs must have a death wish and a short memory.
I posted the following here in SAA during December of last year; for your
enjoyment, a "Post from the Past" culled from my archives:
| From thad Tue Dec 11 21:26:35 2001
| From: th...@thadlabs.com (Thad Floryan)
| Subject: Re: Reuters confirms city 2100' below the waves (!)
| Newsgroups: alt.astrology,alt.prophecies.nostradamus,alt.astronomy,sci.astro,sci.astro.amateur
John Beaderstadt <be...@mindspring.com> wrote:
| [...]
| And one last thing: an industrial society is not going to suddenly die off
| and completely disappear. Anything that could wipe it out and erase its
| artifacts will leave signs of its own passing. It may well be that we
| wouldn't know what was there or what happened to it, but we'd know
| *something* was there, and that something catastrophic occurred.
Consider, for example, the Carolina Bays -- 500,000+ craters most-likely
caused by debris from an aerial comet detonation circa 10,500 years ago.
For a rather detailed scientific study of this (and comparing it to the
Tunguska event), visit URL:
<http://abob.libs.uga.edu/bobk/cbayint.html>
for the 26-page paper entitled:
A RE-EVALUATION OF THE EXTRATERRESTRIAL ORIGIN OF THE CAROLINA BAYS
by J. Ronald Eyton and Judith I. Parkhurst
Paper Number 9, April 1975
archived from the University of Illinois at Urbana Champaign
It's rather technical but still easy to read, and makes a compelling case
for the cometary and not the meteor or asteroid origin of the craters, and
goes into great detail concerning morphometry and impact dynamics.
Such phenomena can easily wipe out traces of any civilization (witness
the dino extinction 65 million years ago) and just think what, say, the
meteor crater in Arizona (some 60,000 years ago) or the Tunguska event (1908)
could do to a population center today. Far fetched? Think back just a few
years ago to the Shoemaker-Levy bombardment of Jupiter. Or Hermes passing
within 500,000 miles of Earth in 1937.
For more info, my notes indicate background reading can be found in the
October 1995 issue of ASTRONOMY, pages 34-41. That article mentions some
recent discoveries re: the Tunguska [15 MegaTon] event of 1908, has one photo
of the 1972 [potential] 10 MegaTon event that just barely missed Earth (the
photo shows it leaving a horizon-to-horizon streak in the sky as it grazed the
upper atmosphere), details of the 1994 cometary bombardment of Jupiter by
Shoemaker-Levy, and additional backgrounders along with proposals for space-
watch and defense programs (e.g., "SpaceGuard", et al).
But, still, the Eyton/Parkhurst article (re: Carolina Bays) is fascinating
and provides cometary models along with other not-readily-available info
concerning mass and effect of impacting objects from space, and it concludes:
The proposed model with shock waves from cometary fragments exploding
above the surface creating a series of similar landforms is conceptually
very simple, and is far less complex than most of the terrestrial models
postulated recently. For geometrically regular forms such as Carolina Bays
we prefer a simple causal mechanism if it is feasible.
[ note: Occam's razor! :-) ]
Examination of impact mechanics and Carolina Bay morphometry eliminates
traditional impact phenomena resulting from meteor swarms or asteroids.
However, the unique orbital and physical characteristics of a comet favor
a model in which a high velocity retrograde comet or a low velocity
prograde comet collided with the Earth. The incoming nucleus approached
from the northwest and fragmented. The fragments, diverging from the main
trajectory, volatized and subsequently exploded in the atmosphere near the
surface. The resultant shock waves created shallow elliptical depressions
which are best displayed in the sandy specimens of the Coastal Plain [of
the USA].
Karol
> As I previously wrote, I agree those programs should be funded and developed.
> Anyone opposing such programs must have a death wish and a short memory.
>
> I posted the following here in SAA during December of last year; for your
> enjoyment, a "Post from the Past" culled from my archives:
> traditional impact phenomena resulting from meteor swarms or asteroids.
> However, the unique orbital and physical characteristics of a comet favor
> a model in which a high velocity retrograde comet or a low velocity
> prograde comet collided with the Earth. The incoming nucleus approached
> from the northwest and fragmented. The fragments, diverging from the main
> trajectory, volatized and subsequently exploded in the atmosphere near the
> surface. The resultant shock waves created shallow elliptical depressions
> which are best displayed in the sandy specimens of the Coastal Plain [of
> the USA].
So, maybe we should place a petition on some website...
--
Karol
Tony Flanders
> As I previously wrote, I agree [that planetary defense programs]
> should be funded and developed.
> Anyone opposing such programs must have a death wish and a short memory.
Memory is not *precisely* the right word for something that may or may
not have happened 10,500 years ago!
In any case, I will state again for the record that I am well aware
of the evidence regarding collisions, I have no death wish, and I
oppose planetary defense programs for the forseeable future, although
no doubt the time will come when they make sense, assuming that we
last that long.
The reason is that I think that the risk from such programs would
vastly outweigh the risk from the asteroids themselves. Not that
asteroids and comets are a trivial threat, but there are many
much larger and more imminent threats, including war, famine,
pestilence, and others.
- Tony Flanders
Karol
> In any case, I will state again for the record that I am well aware
> of the evidence regarding collisions, I have no death wish, and I
> oppose planetary defense programs for the forseeable future, although
> no doubt the time will come when they make sense, assuming that we
> last that long.
Why would they suddenly make sense while they don't for now?
> The reason is that I think that the risk from such programs would
> vastly outweigh the risk from the asteroids themselves. Not that
> asteroids and comets are a trivial threat, but there are many
> much larger and more imminent threats, including war, famine,
> pestilence, and others.
What exactly could be a negative effect of reviving Clementine 2?
--
Karol
Paul Schlyter
Karol <plane...@poczta.onet.pl> wrote:
> tony_f...@yahoo.com (Tony Flanders) wrote in message news:<958c21.020402...@posting.google.com>...
>
>> In any case, I will state again for the record that I am well aware
>> of the evidence regarding collisions, I have no death wish, and I
>> oppose planetary defense programs for the forseeable future, although
>> no doubt the time will come when they make sense, assuming that we
>> last that long.
>
> Why would they suddenly make sense while they don't for now?
sense.
It's a matter of priorities and risks. If you check out the risks
that you'll die of various causes, the figures may end up something
like this:
50% Heart and lung diseases
30% Cancer
.............................
1% Traffic accidents
1% Suicide
0.5% Other accidents
0.2% Volcanic eruptions, floods, storms, etc
.............................
0.0001% Meteor, comet or asteroid impact
0.0000001% Nearby nova or supernova
Now, what's the point of spending large resources to fight the very
small risk of a fatal meteor/asteroid impact unless we've first
eliminated the other, much larger, risks?
You can also consider this: how many times did we detect an asteroid
passing closer to us than the Moon? A few times -- but in all these
cases the asteroids were the size of a house, and upon impact on the
Earth, such an object would only cause local damage.
Statistically, for each asteroid actually impacting the Earth, we can
expect about ONE THOUSAND asteroids passing nearer than the Moon but
missing the Earth.
In 2004 the asteroid Toutatis will pass very near us, at some 8 times
the Moon's distance. Statistically, we can expect some 50,000 to
100,000 such close passes of asteroids for each actual asteroid impact
on the Earth.
--
----------------------------------------------------------------
Paul Schlyter, Swedish Amateur Astronomer's Society (SAAF)
Grev Turegatan 40, S-114 38 Stockholm, SWEDEN
e-mail: pausch at saaf dot se
WWW: http://hem.passagen.se/pausch/index.html
http://home.tiscali.se/~pausch/
JMc
five mikes a day, or people who drive around wearing their seat belts ;-)
The statistics you site are convincing and they demonstrate how people
prefer to blame their troubles on outside factors. The best long-term
insurance policy for the human species is to establish a presence on
other planets.
Jim McSheehy
Bill Ferris
>In any case, I will state again for the record that I am well aware
>of the evidence regarding collisions, I have no death wish, and I
>oppose planetary defense programs for the forseeable future, although
>no doubt the time will come when they make sense, assuming that we
>last that long.
>
>The reason is that I think that the risk from such programs would
>vastly outweigh the risk from the asteroids themselves. Not that
>asteroids and comets are a trivial threat, but there are many
>much larger and more imminent threats, including war, famine,
>pestilence, and others.
I would add that computer modelling suggests the likely scenario is that we
would discover an Earth impactor many years, even decades, prior to impact.
This gives ample time to study the object and determine the best response to
that specific threat.
Not all asteroids and comets are alike, neither in composition nor orbital
characteristics. A number of factors would have to be studied and understood
before an effective response could be determined. Do we move the object?
Annihilate it? Focus on evacuating populated regions? No one option suffices
for all potential impactors. And no one approach to any of the above options
will work for all potential impactors.
The prudent course is to continue to fund surveys to catalog all 1 km and
larger (civilization killers) NEOs. We should also fund robotic missions to
selected 'roids and comets to study composition. These missions will yield
answers to questions about how best to deal with any future impactors.
Additionally, we'll undoubtedly gain a better understanding of the origin of
the Solar System, which will shed light on the story of Earth's origin, too.
I'm with Tony--perhaps for different reasons--that investing in space-based
planet defense systems, now, is not a good idea.
Regards,
Bill Ferris
"Cosmic Voyage: The Online Resource for Amateur Astronomers"
URL: http://www.cosmic-voyage.net
=============
Email: Remove "ic" from .comic above to respond
Tony Flanders
> I oppose planetary defense programs for the forseeable future, although
> no doubt the time will come when they make sense, assuming that we
> last that long.
Karol wondered:
> Why would they suddenly make sense while they don't for now?
As Paul Schlyter says, eventually but not suddenly.
Partly a matter of working down the list of hazards, again as
Paul Schlyter says. We never worried about diseases of affluence
(diabetes, etc.) as long as most people were dying of infectious
diseases and malnutrition, and rightly so. Now that relatively
few people in the industrialized world die of infectious disease
or malnutrition, diseases of civilization loom large.
Also a matter of maturing technology. Right at the moment, it is
hard to imagine what we could possibly do about any asteroid big
enough to be a serious threat. Fortunately, the chances that
such an asteroid will wander by in the next few hundred years
are negligible, which gives us plenty of breathing room. Who
knows what technology will look like by then?
> What exactly could be a negative effect of reviving Clementine 2?
Clementine 2 per se would probably be completely innocuous, but
anti-asteroid technology bears an uncomfortable resemblance to
ABM technology, which is anything but innocuous.
There is also a serious question of diversion of funds; it is one
thing to study asteroids (sure, why ever not!) but as I said,
actually doing something about them would require technology
far in advance of anything we posess, and the money spent to
develop that could save vastly more lives if devoted (say) to
fighting infectious diseases -- which still kill plenty of
people even in the industrialized world (think AIDS and
antibiotic-resistant tuberculosis) and vast numbers of people
in the unindustrialized world (think malaria).
- Tony Flanders
Karol
> > Why would they suddenly make sense while they don't for now?
>
> They won't "suddenly" make sense then, but they may "gradually" make
> sense.
But what will "gradually" happen that will make the planetary defense
a better idea than it is now?
> It's a matter of priorities and risks. If you check out the risks
> that you'll die of various causes, the figures may end up something
> like this:
>
> 50% Heart and lung diseases
> 30% Cancer
> .............................
> 1% Traffic accidents
> 1% Suicide
> 0.5% Other accidents
> 0.2% Volcanic eruptions, floods, storms, etc
> .............................
> 0.0001% Meteor, comet or asteroid impact
> 0.0000001% Nearby nova or supernova
I have seen a similar listing in some book. It placed asteroids in the
middle and it was FOLLOWED by plane crashes.
> Now, what's the point of spending large resources to fight the very
> small risk of a fatal meteor/asteroid impact unless we've first
> eliminated the other, much larger, risks?
It will not be the statistics that would kill you but the shockwave
and heat followed by nuclear winter and starvation. We would be
talking a very diffrent way if Tunguska hit Petersburg instead of
Syberia. Statistics can easily be manipulated either way but it is not
that simple. Asteroids are not an "out of this world phenomennon".
They are reality and they do fall on Earth.
> You can also consider this: how many times did we detect an asteroid
> passing closer to us than the Moon? A few times -- but in all these
> cases the asteroids were the size of a house, and upon impact on the
> Earth, such an object would only cause local damage.
As you have probably noticed after the 2002 EM7 flyby, we cannot
detect Tunguskas at such distances no matter whether the conditions
are favorable or not. And Tunguska was not so local.
> Statistically, for each asteroid actually impacting the Earth, we can
> expect about ONE THOUSAND asteroids passing nearer than the Moon but
> missing the Earth.
So what? As long as that one in a thousand hits the Earth, the need
for means of deflecting it is obvious. The worst thing about asteroids
is that we do not know WHEN it will happen and therefore some people
cannot perceive them as a serius threat. If we learn how to deflect
even the small ones, we will be able to install sufficient technology
by the time the really big one comes. Dinosaurs didn't have a
planetary defense system. Are humans dinosaurs?
> In 2004 the asteroid Toutatis will pass very near us, at some 8 times
> the Moon's distance. Statistically, we can expect some 50,000 to
> 100,000 such close passes of asteroids for each actual asteroid impact
> on the Earth.
If we revive Clementine 2 it will intercept Toutatis in 2004 and begin
the tests.
--
Karol
Brian Tung
> But what will "gradually" happen that will make the planetary defense
> a better idea than it is now?
Actually, I seem to recall that Tony Flanders said something a little
different from Paul's interpretation. Here is what he actually wrote:
Tony:
> The reason is that I think that the risk from such programs would
> vastly outweigh the risk from the asteroids themselves.
Not that *other* risks outweigh the asteroid risk, but that the risk
*from asteroid defense programs* outweigh the asteroid risk, and vastly
so--that is Tony's thinking. Interestingly, Tony is not the first to
think that. Carl Sagan, in his book Pale Blue Dot, wrote a chapter
("The Marsh of Camarina") describing this problem.
The problem, as Sagan put it, is that if you can reliably deflect an
asteroid on a collision course in order to put it on a safe course, you
can also reliably deflect an asteroid on a safe course to put it on a
collision course. He is not put off by "only a madman" arguments, since
there are plenty of madmen. (I certainly agree with him on that.) Such
a plan could also--with great effort--be hidden from just about everyone
until it was too late.
However, the whole premise of that particular risk seems specious. It
is hardly clear at all to me that it's just as easy to change a safe
course to a collision course as vice versa. There are just so many more
safe courses than collision courses that it seems it is *much* easier
to deflect than to direct. For some reason, Sagan himself points this
out later in that same chapter.
I don't know the particular reason that Tony thinks the risks associated
with those programs are much worse than the risks from the asteroids
themselves.
Paul:
> It's a matter of priorities and risks. If you check out the risks
> that you'll die of various causes, the figures may end up something
> like this:
>
> [snipped table]
Karol:
> I have seen a similar listing in some book. It placed asteroids in the
> middle and it was FOLLOWED by plane crashes.
So have I. However, such tables abstract away the fact that there are
*two* factors involved in such figures, not one--and those two may not
be that well correlated with each other.
In estimating the likelihood of dying by any external (and context-free)
event, we must take into account both the frequency *and* the virulence
of that event. An event that kills a person a day (on average) produces
the same mean death rate as one that kills 5 billion people every 15
million years or so. However, that only goes to show that mean death
rate is sometimes misleading.
The kill-a-day event will produce, over a period of a year, an average
of 365 deaths. The exact number of deaths per year will vary, of course,
and the distribution will be normal--that is, a bell curve. And unless
the individual event's death count has an extraordinary variance, the
total deaths per year will have a smallish standard deviation--perhaps
on the order of 20 or so, if the death count is geometrically distributed,
or one part in 18. If you count deaths over an ordinary human lifetime,
the relative deviation is even smaller--one part in 150, say.
The big asteroid hit, however, is much more like the "5 billion people
every 15 million years" event than the other. This produces a tremendous
skew in the death count distribution, over a period as small as a year,
or even a person's lifetime. In 14,999,999 out of every 15,000,000 years,
nothing. That one year, everybody (or most everybody) dies.
I've found that the reaction of people to such a skewed risk varies
enormously. Some people look at the huge time spans involved, ignoring
the equally huge death tolls, and say, "Eh, what's to worry about?"
Others look at it exactly the other way, and respond accordingly. We
don't really understand very well how we should address this kind of
risk.
Paul:
> Statistically, for each asteroid actually impacting the Earth, we can
> expect about ONE THOUSAND asteroids passing nearer than the Moon but
> missing the Earth.
Karol:
> So what? As long as that one in a thousand hits the Earth, the need
> for means of deflecting it is obvious.
Well, this argument can quickly be deflated by replacing "thousand" with
"million" or "billion" or "trillion." At some point, the risk obviously
becomes too little to worry about. Nothing in the wording of your
argument addresses that. Where on your slippery slope do you intend to
draw the line? And why? That reason for drawing the line where you do,
*that* is the real argument that you wish to propose.
Once you set down the reason for drawing the line where you do, it should
be evident why defense can gradually become worth the money to do--it is
because other risks become relatively smaller against the more or less
constant risk of asteroid collisions.
Brian Tung <br...@isi.edu>
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt
Karol
> The statistics you site are convincing and they demonstrate how people
> prefer to blame their troubles on outside factors. The best long-term
> insurance policy for the human species is to establish a presence on
> other planets.
As I already mentioned, I have seen more than one listing like this
and this is far from convincing because in some of those asteroids
were placed somewhere in the middle of the list or even close to top 5
and were always followed by things like airplane accidents. What do
you think were the odds of 2 airplanes crashing into WTC? And yet, it
happened. Statistics has nothing to do with asteroids because it can
easily be maniputed either way since we do not know some important
things on where in the Solar System they actually are. Establishing
human presence on other planets is much more difficult than installing
a planetary defense system and certainly far less affordable than a
tiny little test probe like Clementine 2.
--
Karol
Karol
> I would add that computer modelling suggests the likely scenario is that we
> would discover an Earth impactor many years, even decades, prior to impact.
> This gives ample time to study the object and determine the best response to
> that specific threat.
And common practice suggests that we can see in advance only the
REALLY big ones and yet even those can be missed. Automated telescopes
do not cover sufficient portion of the sky as already proven by the
fact that we still have amateur comet and asteroid discoveries. And
there was a comet back in 1997 that went undetected until later
investigations took place because everyone was distracted by H-B's
show.
> Not all asteroids and comets are alike, neither in composition nor orbital
> characteristics. A number of factors would have to be studied and understood
> before an effective response could be determined. Do we move the object?
> Annihilate it? Focus on evacuating populated regions? No one option suffices
> for all potential impactors. And no one approach to any of the above options
> will work for all potential impactors.
We won't know until we actually test some technology and Clementine 2
is designed to do it. There are important factors that cannot be
determined theoretically nor by just looking at the asteroids with
things like NEAR-Shoemaker.
> The prudent course is to continue to fund surveys to catalog all 1 km and
> larger (civilization killers) NEOs. We should also fund robotic missions to
> selected 'roids and comets to study composition. These missions will yield
> answers to questions about how best to deal with any future impactors.
> Additionally, we'll undoubtedly gain a better understanding of the origin of
> the Solar System, which will shed light on the story of Earth's origin, too.
Even NASA put that poor rhetorics of the nineties aside. We need to
study asteroids as well, but just looking at them is not enough to
know how to deflect them.
> I'm with Tony--perhaps for different reasons--that investing in space-based
> planet defense systems, now, is not a good idea.
So you want to invest in it when it is 3 minutes to impact right?
--
Karol
Karol
> Partly a matter of working down the list of hazards, again as
> Paul Schlyter says. We never worried about diseases of affluence
> (diabetes, etc.) as long as most people were dying of infectious
> diseases and malnutrition, and rightly so. Now that relatively
> few people in the industrialized world die of infectious disease
> or malnutrition, diseases of civilization loom large.
Why do we have to always start worrying when it is too late?
> Also a matter of maturing technology. Right at the moment, it is
> hard to imagine what we could possibly do about any asteroid big
> enough to be a serious threat. Fortunately, the chances that
> such an asteroid will wander by in the next few hundred years
> are negligible, which gives us plenty of breathing room. Who
> knows what technology will look like by then?
The technology won't be sufficient in the future if we don't start
developing it now. And we just now that no really large asteroid in
the inner parts of the Solar System will hit Earth until 2061. After
that, even the IAU has no idea since there were no ephemeris
calculated beyond that date. Comets are far less detectable at great
distances and are for from being thorougly catalogued.
> > What exactly could be a negative effect of reviving Clementine 2?
>
> Clementine 2 per se would probably be completely innocuous, but
> anti-asteroid technology bears an uncomfortable resemblance to
> ABM technology, which is anything but innocuous.
So if it is innocous, why don't we give it a go?
> There is also a serious question of diversion of funds; it is one
> thing to study asteroids (sure, why ever not!) but as I said,
> actually doing something about them would require technology
> far in advance of anything we posess, and the money spent to
> develop that could save vastly more lives if devoted (say) to
> fighting infectious diseases -- which still kill plenty of
> people even in the industrialized world (think AIDS and
> antibiotic-resistant tuberculosis) and vast numbers of people
> in the unindustrialized world (think malaria).
Clementine 2 would not really require any diversion of funds since it
is funded by DoD and not NASA and only diversion that would occur is
using the money to save millions of human lives instead of killing
people.
--
Karol
Bill Ferris
>And common practice suggests that we can see in advance only the
>REALLY big ones and yet even those can be missed.
The current goal is to detect 90% of all 1 km and larger NEOs. That size is
considered the threshhold for an object which be globally catastrophic wherever
it hit, should it hit Earth. Modelling suggest approximately 1000 such objects
orbit the Sun. Of the ~1800 known NEOs, 395 are 1 km or larger and potentially
hazardous, according to the IAU Minor Planet Center:
http://cfa-www.harvard.edu/iau/lists/Unusual.html
>Automated telescopes do not cover sufficient portion of the sky as
>already proven by the fact that we still have amateur comet and
>asteroid discoveries.
The fact that NEOs are discovered by individuals or groups outside the
professional surveys is *not* proof that the surveys cover an insufficient
portion of the sky. In fact, no survey will ever get every object. Coverage in
the northern hemisphere is sufficient, given the performance of LINEAR, LONEOS,
Spacewatch, other professional surveys and amateurs involved specifically in
asteroid surveys. Coverage in the southern hemisphere is not sufficient. In
fact, it's practically non-existent. Too bad Australia decided not to fund a
southern hemisphere survey. That wouldn't have completely made up for the
deficiency but it would have been a good start.
>And there was a comet back in 1997 that went undetected until later
>investigations took place because everyone was distracted by H-B's
>show.
That's sheer hyperbole. The fact is that no survey or group of surveys will
ever be 100% effective at detecting all inner solar system objects. Anywhere
from 10 to 100 "house-sized" asteroids pass within two lunar orbit radii of
Earth during a given year. Astronomers don't miss them because of being
distracted. They're missed because they're typically too faint to be detected
by current survey instruments. Since these objects do not pose a global threat
to Earth, they're not a first priority concern. Perhaps, this will change when
the Spaceguard Survey goal of cataloging 90% of all 1 km and larger NEOs is
complete.
> [Bill Ferris wrote:]
>> Not all asteroids and comets are alike, neither in composition nor orbital
>> characteristics. A number of factors would have to be studied and
>> understood before an effective response could be determined. Do we
>> move the object? Annihilate it? Focus on evacuating populated regions?
>> No one option suffices for all potential impactors. And no one approach
>> to any of the above options will work for all potential impactors.
>
>We won't know until we actually test some technology and Clementine 2
>is designed to do it. There are important factors that cannot be
>determined theoretically nor by just looking at the asteroids with
>things like NEAR-Shoemaker.
On the contrary, the more we study near-Earth asteroids and comets, the better
we'll understand their geophysiology. This increased knowledge will, in turn,
allow us to make better informed decisions as to how to respond to a legitimate
threat from and NEO.
Developing space-based anti-NEO technology at this stage of the game is like
hitting the panic button. We'll spend trillions to get something flying. It'll
be up there for a decade, perhaps two, without being needed and the public will
justifiably ask, "Why do we continue to pour money hand over fist into this
useless, white elephant technology." Not only will the "defense system" die and
ugly death on the floor of Congress, but it will likely take legitimate solar
system research down the tubes with it.
>> The prudent course is to continue to fund surveys to catalog all 1 km and
>> larger (civilization killers) NEOs. We should also fund robotic missions to
>> selected 'roids and comets to study composition. These missions will yield
>> answers to questions about how best to deal with any future impactors.
>> Additionally, we'll undoubtedly gain a better understanding of the origin
>> of the Solar System, which will shed light on the story of Earth's origin,
>> too.
>
>Even NASA put that poor rhetorics of the nineties aside. We need to
>study asteroids as well, but just looking at them is not enough to
>know how to deflect them.
Who suggested, "just looling at them?" Certainly, not me. Robotic missions are
relatively inexpensive, and able to produce a lot of useful information: the
size of the asteroid; mass; density; and composition. This kind of information
is *essential* to any plan to either move or annihilate a potential impactor.
>> I'm with Tony--perhaps for different reasons--that investing in space-based
>> planet defense systems, now, is not a good idea.
>
>So you want to invest in it when it is 3 minutes to impact right?
You talk about it as though an NEO impact is a foregone conclusion within the
next few years or decades. That's just plain wrong.
The fact is that we don't know when the next impactor will hit. Analysis of
lunar and Earth impact craters suggest something big (1 km or larger) hits
Earth every 200,000 to 400,000 years. If you balance the potential loss of
human life in such a catastrophic event, the odds of dying in an impact are
about equal to those of dying in a plane crash. Now, planes crash every day.
Big asteroids hit every 300,000 years or so.
By surveying the larger NEOs, we actually reduce the risk we face from these
objects. When we reach that 90% goal, we'll likely be able to say with a fair
degree of certainty, "Nine out of ten large potentially hazardous objects are
catalogued and not one will hit Earth in the next 100 years."
That's quite an effective insurance policy. Much more effective than any
space-based defense system.
Paul Schlyter
>
>>> Why would they suddenly make sense while they don't for now?
>>
>> They won't "suddenly" make sense then, but they may "gradually" make
>> sense.
>
> But what will "gradually" happen that will make the planetary defense
> a better idea than it is now?
significant. The probability that an asteroid impact with more than
local damage will occur during the next 100 years is extremely low;
the probability it will happen in the next several million years is
much much higher.
>> It's a matter of priorities and risks. If you check out the risks
>> that you'll die of various causes, the figures may end up something
>> like this:
>>
>> 50% Heart and lung diseases
>> 30% Cancer
>> .............................
>> 1% Traffic accidents
>> 1% Suicide
>> 0.5% Other accidents
>> 0.2% Volcanic eruptions, floods, storms, etc
>> .............................
>> 0.0001% Meteor, comet or asteroid impact
>> 0.0000001% Nearby nova or supernova
>
> I have seen a similar listing in some book. It placed asteroids in the
> middle and it was FOLLOWED by plane crashes.
accidents" I meant mostly car crashes.... <g> Going by plane or
train is indeed much safer than going by car - but people still go by
car a lot. Why do they do that? Do they want to die? <g>
>> Now, what's the point of spending large resources to fight the very
>> small risk of a fatal meteor/asteroid impact unless we've first
>> eliminated the other, much larger, risks?
>
> It will not be the statistics that would kill you but the shockwave
> and heat followed by nuclear winter and starvation.
> We would be talking a very diffrent way if Tunguska hit Petersburg
> instead of Syberia.
that for each Tunguska-sized body hitting Petersburg we could expect
thousands of Tunguska-sized bodies hitting Siberia.
> Statistics can easily be manipulated either way but it is not
> that simple. Asteroids are not an "out of this world phenomennon".
> They are reality and they do fall on Earth.
damage do fall rarely on the Earth, from a human perspective.
>> You can also consider this: how many times did we detect an asteroid
>> passing closer to us than the Moon? A few times -- but in all these
>> cases the asteroids were the size of a house, and upon impact on the
>> Earth, such an object would only cause local damage.
>
> As you have probably noticed after the 2002 EM7 flyby, we cannot
> detect Tunguskas at such distances no matter whether the conditions
> are favorable or not.
claim we cannot detect it, yet we know about it. How come?
> And Tunguska was not so local.
global catastrophy. Many more people are killed by e.g. floods or
earthquakes than by meteor/asteroid impacts.
>> Statistically, for each asteroid actually impacting the Earth, we can
>> expect about ONE THOUSAND asteroids passing nearer than the Moon but
>> missing the Earth.
>
> So what? As long as that one in a thousand hits the Earth, the need
> for means of deflecting it is obvious.
passing closer to us than the Moon, please estimate the probable
duration until a similar sized asteroid actually hits the Earth.
Yep, it will most likely not happen in a very loooooooong time!
> The worst thing about asteroids is that we do not know WHEN it
> will happen and therefore some people cannot perceive them as a
> serius threat.
earthquakes, car crashes or diseases: we don't know beforehand
WHEN or WHERE they will happen. That's why people don't perceive
a car ride as a danger either.....
Just think about all the possible dangers to your life. Then assume
a near-worst case scenario not just for asteroid impacts but for all
other dangers as well -- and you'll be surprised you're still alive!
> If we learn how to deflect even the small ones, we will be able
> to install sufficient technology by the time the really big one
> comes. Dinosaurs didn't have a planetary defense system. Are humans
> dinosaurs?
or so (a very short time span from a cosmic perspective) we'll
probably have learnt where most, if not all, NEA's large enough to
pose a serious threat to us travel in their orbits, and so we'll be
able to predict future impacts enough (i.e. a few decades or more) in
advance to construct a deflection system when there really is such a
threat.
>> In 2004 the asteroid Toutatis will pass very near us, at some 8 times
>> the Moon's distance. Statistically, we can expect some 50,000 to
>> 100,000 such close passes of asteroids for each actual asteroid impact
>> on the Earth.
>
> If we revive Clementine 2 it will intercept Toutatis in 2004 and begin
> the tests.
2004....
And you ignore the statistics and assume an almost worst-case
scenario for asteroid impacts but not so for other dangers to our
lives. That's not a fair comparison...
John Savard
wrote, in part:
>How the hell did this get women-centric? I don't get where you are going
>with this unless you are implying that there is some kind of
>eligible-woman-shortage which causes the men to have to make lots of money
>to try to get one?
It's my pet theory to explain why we have wars, and how come we have
to pay taxes.
John Savard
http://members.shaw.ca/quadibloc/index.html
Tony Flanders
> The big asteroid hit, however, is much more like the "5 billion people
> every 15 million years" event than the other...
> I've found that the reaction of people to such a skewed risk varies
> enormously...
On top of that, although we can make some vaguely responsible guesses
about the effect an asteroid impact would have on the environment
based both on physical modelling and on evidence of past impacts,
it is anybody's guess what those environmental changes would mean
for humanity.
At one extreme, one might guess that we would take them in stride
with relatively little harm. We are, after all, the most adaptable
species on Earth measured in terms of the variety of niches in which
we flourish.
At the opposite extreme, one might predict the complete annihilation
of the species. After all, our adaptability is basically a function
of social organization; individual human beings are nearly helpless.
And the more advanced the civilization, the more dependent on social
organization. Let that organization collapse and who knows what
might happen?
Smart money is for something in between: massive effect, but
humanity surviving. We do, after all, have historical experience
of civilizatons surviving some mighty gigantic calamities, notably
epidemics which have killed more than 50% of entire populations.
Rather frequently, for that matter. And by no means inconceivable
that it will happen again, I might add. And may be happening now.
Moreover, there is a big philosophical question of whether the
extermination of humanity would be an evil transcending all the
individual deaths involved. Personally, I tend to precisely the
opposite view -- 50% dying is a tragedy because of the sorrow
felt by the other 50%, but maybe 100% dying is a blessing --
the universe being rid of another pest species. But I can
certainly understand both points of view, and everything in
between.
Presumably, the people who advocate colonizing other planets as
a precaution against being hit by an asteroid or comet both
believe in the total-extermination scenario and also place
a high value on the survival of humanity per se as opposed to
the survival of individuals. After all, a colony on Mars
wouldn't make the people on Earth feel any better if they
were all wiped out by an asteroid. Or would it?
But any way you slice it, it is mighty hard to claim that the
risk of asteroid or comet collisions is comparable in *any*
terms -- either in probability or in number of people potentially
effected -- to numerous other threats that can be imagined.
- Tony Flanders
Karol
> The current goal is to detect 90% of all 1 km and larger NEOs. That size is
> considered the threshhold for an object which be globally catastrophic wherever
> it hit, should it hit Earth. Modelling suggest approximately 1000 such objects
> orbit the Sun. Of the ~1800 known NEOs, 395 are 1 km or larger and potentially
> hazardous, according to the IAU Minor Planet Center:
> http://cfa-www.harvard.edu/iau/lists/Unusual.html
First, read this:
http://www.spaceflightnow.com/news/n0204/05asteroid/
> >Automated telescopes do not cover sufficient portion of the sky as
> >already proven by the fact that we still have amateur comet and
> >asteroid discoveries.
>
> The fact that NEOs are discovered by individuals or groups outside the
> professional surveys is *not* proof that the surveys cover an insufficient
> portion of the sky. In fact, no survey will ever get every object. Coverage in
Yes it is. Amateurs are not as well equipped as those surveys and they
find bright objects of 10 mag or so. A survey that can miss something
like that is far from sufficient. And I am not talking "complete
coverage".
> the northern hemisphere is sufficient, given the performance of LINEAR, LONEOS,
> Spacewatch, other professional surveys and amateurs involved specifically in
> asteroid surveys. Coverage in the southern hemisphere is not sufficient. In
> fact, it's practically non-existent. Too bad Australia decided not to fund a
> southern hemisphere survey. That wouldn't have completely made up for the
> deficiency but it would have been a good start.
We've got insufficient coverage in the north and virtually nothing in
the south. And that means we miss A LOT.
> >And there was a comet back in 1997 that went undetected until later
> >investigations took place because everyone was distracted by H-B's
> >show.
>
> That's sheer hyperbole. The fact is that no survey or group of surveys will
> ever be 100% effective at detecting all inner solar system objects. Anywhere
> from 10 to 100 "house-sized" asteroids pass within two lunar orbit radii of
> Earth during a given year. Astronomers don't miss them because of being
> distracted. They're missed because they're typically too faint to be detected
> by current survey instruments. Since these objects do not pose a global threat
> to Earth, they're not a first priority concern. Perhaps, this will change when
> the Spaceguard Survey goal of cataloging 90% of all 1 km and larger NEOs is
> complete.
Astronomers missed the 1997 comet BECAUSE they were distracted. I'll
give you a link on that later.
> >We won't know until we actually test some technology and Clementine 2
> >is designed to do it. There are important factors that cannot be
> >determined theoretically nor by just looking at the asteroids with
> >things like NEAR-Shoemaker.
>
> On the contrary, the more we study near-Earth asteroids and comets, the better
> we'll understand their geophysiology. This increased knowledge will, in turn,
> allow us to make better informed decisions as to how to respond to a legitimate
> threat from and NEO.
There must be some factors that we are unaware of because we never
actually hit a thing like that. Looking at a glass of water is one
thing but actually stirring it and seeing what happens is a
compeletely different matter.
> Developing space-based anti-NEO technology at this stage of the game is like
> hitting the panic button. We'll spend trillions to get something flying. It'll
> be up there for a decade, perhaps two, without being needed and the public will
> justifiably ask, "Why do we continue to pour money hand over fist into this
> useless, white elephant technology." Not only will the "defense system" die and
> ugly death on the floor of Congress, but it will likely take legitimate solar
> system research down the tubes with it.
For now the Clementine 2 would be enough. It won't affect exploration
of the Solar System because it would be funded by DoD and not NASA and
because it costs only about 200 M$.
> >> The prudent course is to continue to fund surveys to catalog all 1 km and
> >> larger (civilization killers) NEOs. We should also fund robotic missions to
> >> selected 'roids and comets to study composition. These missions will yield
> >> answers to questions about how best to deal with any future impactors.
> >> Additionally, we'll undoubtedly gain a better understanding of the origin
> >> of the Solar System, which will shed light on the story of Earth's origin,
> >> too.
> >
> >Even NASA put that poor rhetorics of the nineties aside. We need to
> >study asteroids as well, but just looking at them is not enough to
> >know how to deflect them.
>
> Who suggested, "just looling at them?" Certainly, not me. Robotic missions are
> relatively inexpensive, and able to produce a lot of useful information: the
> size of the asteroid; mass; density; and composition. This kind of information
> is *essential* to any plan to either move or annihilate a potential impactor.
Size, density and not much more. Essential are the mechanical
properties of the surface and its response to factors disturbing it.
> >> I'm with Tony--perhaps for different reasons--that investing in space-based
> >> planet defense systems, now, is not a good idea.
> >
> >So you want to invest in it when it is 3 minutes to impact right?
>
> You talk about it as though an NEO impact is a foregone conclusion within the
> next few years or decades. That's just plain wrong.
Just look at the news I linked at the beginning of this post. We DO
NOT KNOW. The coverage is insufficient and precision of measurements
and calculations isn't sufficient either.
> The fact is that we don't know when the next impactor will hit. Analysis of
> lunar and Earth impact craters suggest something big (1 km or larger) hits
> Earth every 200,000 to 400,000 years. If you balance the potential loss of
> human life in such a catastrophic event, the odds of dying in an impact are
> about equal to those of dying in a plane crash. Now, planes crash every day.
> Big asteroids hit every 300,000 years or so.
As someone mentioned earlier this is a misconception based on
confusing average yearly rates of deaths with the real ones.
> By surveying the larger NEOs, we actually reduce the risk we face from these
> objects. When we reach that 90% goal, we'll likely be able to say with a fair
> degree of certainty, "Nine out of ten large potentially hazardous objects are
> catalogued and not one will hit Earth in the next 100 years."
>
> That's quite an effective insurance policy. Much more effective than any
> space-based defense system.
I would not feel safe if you told me only one bullet out of ten will
hit me when I go straight under fire.
--
Karol
Karol
> In the long run the risk of an asteroidal impact will become
> significant. The probability that an asteroid impact with more than
> local damage will occur during the next 100 years is extremely low;
> the probability it will happen in the next several million years is
> much much higher.
Please read this:
http://www.spaceflightnow.com/news/n0204/05asteroid/
> >> It's a matter of priorities and risks. If you check out the risks
> >> that you'll die of various causes, the figures may end up something
> >> like this:
> >>
> >> 50% Heart and lung diseases
> >> 30% Cancer
> >> .............................
> >> 1% Traffic accidents
> >> 1% Suicide
> >> 0.5% Other accidents
> >> 0.2% Volcanic eruptions, floods, storms, etc
> >> .............................
> >> 0.0001% Meteor, comet or asteroid impact
> >> 0.0000001% Nearby nova or supernova
> >
> > I have seen a similar listing in some book. It placed asteroids in the
> > middle and it was FOLLOWED by plane crashes.
>
> Plane crashes wasn't included at all in my list here -- with "traffic
> accidents" I meant mostly car crashes.... <g> Going by plane or
> train is indeed much safer than going by car - but people still go by
> car a lot. Why do they do that? Do they want to die? <g>
Plane crashes were on the list I saw in some book.
> >> Now, what's the point of spending large resources to fight the very
> >> small risk of a fatal meteor/asteroid impact unless we've first
> >> eliminated the other, much larger, risks?
> >
> > It will not be the statistics that would kill you but the shockwave
> > and heat followed by nuclear winter and starvation.
>
> True, however statistics can tell us the risk of this to happen.
Statistics is often misleading as already mentioned by others.
> > We would be talking a very diffrent way if Tunguska hit Petersburg
> > instead of Syberia.
>
> Also true; however Petersburg is so much much smaller than Siberia
> that for each Tunguska-sized body hitting Petersburg we could expect
> thousands of Tunguska-sized bodies hitting Siberia.
Petersburg was on the same latitude as Tunguska. Would the object
impact a few hours earlier and there would be no Petersburg there and
a planetary defense system installed in orbit by now.
> > As you have probably noticed after the 2002 EM7 flyby, we cannot
> > detect Tunguskas at such distances no matter whether the conditions
> > are favorable or not.
>
> If so, how come we know about 2002 EM7 ????? Here you seem to
> claim we cannot detect it, yet we know about it. How come?
EM7 was detected by accident AFTER it passed its closest point but
then astronomers calculated where it was earlier. Some people thought
it was that because it came from the direction where the Sun's glare
makes observations impossible, but a guy who actually does surveys
said objects of that size and in that distance are NOT detected at all
no matter whether the Sun plays a role or not.
> > And Tunguska was not so local.
>
> Tunguska was barely a regional catastrophy -- it was definitely not a
> global catastrophy. Many more people are killed by e.g. floods or
> earthquakes than by meteor/asteroid impacts.
Look at the area where trees were flattened. Now project it on a
European country.
> >> Statistically, for each asteroid actually impacting the Earth, we can
> >> expect about ONE THOUSAND asteroids passing nearer than the Moon but
> >> missing the Earth.
> >
> > So what? As long as that one in a thousand hits the Earth, the need
> > for means of deflecting it is obvious.
>
> You don't get it, do you? Using the current rate of such asteroids
> passing closer to us than the Moon, please estimate the probable
> duration until a similar sized asteroid actually hits the Earth.
> Yep, it will most likely not happen in a very loooooooong time!
Wrong, look at the link I gave you. The fact that it may happen ones
in a 50 Myrs does not mean it will happen IN 50 Myrs. It may happen
tomorrow. And last time actually was 65 Gyrs ago.
> > The worst thing about asteroids is that we do not know WHEN it
> > will happen and therefore some people cannot perceive them as a
> > serius threat.
>
> That's nothing unique for asteroids! It's the same with floods,
> earthquakes, car crashes or diseases: we don't know beforehand
> WHEN or WHERE they will happen. That's why people don't perceive
> a car ride as a danger either.....
But we eventually could predict impacts by asteroids and car crashes
will always remain unpredictable.
> Just think about all the possible dangers to your life. Then assume
> a near-worst case scenario not just for asteroid impacts but for all
> other dangers as well -- and you'll be surprised you're still alive!
>
> > If we learn how to deflect even the small ones, we will be able
> > to install sufficient technology by the time the really big one
> > comes. Dinosaurs didn't have a planetary defense system. Are humans
> > dinosaurs?
>
> Dinosaurs didn't monitor NEA's -- we do. Within only a hundred years
> or so (a very short time span from a cosmic perspective) we'll
> probably have learnt where most, if not all, NEA's large enough to
> pose a serious threat to us travel in their orbits, and so we'll be
> able to predict future impacts enough (i.e. a few decades or more) in
> advance to construct a deflection system when there really is such a
> threat.
Dinosaurs had no means of deflecting asteroids and humans have no
means of deflecting asteroids now. We miss most of them and even if we
detect the "killer" we would only feel better because we would know
what hit us and dinos didn't.
> >> In 2004 the asteroid Toutatis will pass very near us, at some 8 times
> >> the Moon's distance. Statistically, we can expect some 50,000 to
> >> 100,000 such close passes of asteroids for each actual asteroid impact
> >> on the Earth.
> >
> > If we revive Clementine 2 it will intercept Toutatis in 2004 and begin
> > the tests.
>
> There's no need to deflect Toutatis now -- it won't impact the Earth in
> 2004....
Clementine 2 was supposed to shoot at it by 2000 so it may well do it
in 2004. Toutatis is no threat but it is good for the tests because
Clementine 2 was originally developed for this particular asteroid.
Therefore it would not require additional funds for studying how to
get C2 there.
> And you ignore the statistics and assume an almost worst-case
> scenario for asteroid impacts but not so for other dangers to our
> lives. That's not a fair comparison...
Ignoring asteroids is not a fair comparison.
--
Karol
Karol
> At one extreme, one might guess that we would take them in stride
> with relatively little harm. We are, after all, the most adaptable
> species on Earth measured in terms of the variety of niches in which
> we flourish.
Bugs and rats are the most adaptable species.
> At the opposite extreme, one might predict the complete annihilation
> of the species. After all, our adaptability is basically a function
> of social organization; individual human beings are nearly helpless.
> And the more advanced the civilization, the more dependent on social
> organization. Let that organization collapse and who knows what
> might happen?
It is not the matter of every individual being killed but of wiping
out the civilization as such. It would be "back to stoneage" for that
few who would somehow survive. WTC crippled NYC for some time. Imagine
something 1000 times worse than WTC and spread all over the world.
> But any way you slice it, it is mighty hard to claim that the
> risk of asteroid or comet collisions is comparable in *any*
> terms -- either in probability or in number of people potentially
> effected -- to numerous other threats that can be imagined.
It is not compatible in terms of frequency and that causes confusion.
--
Karol
Paul Schlyter
> Paul:
>> It's a matter of priorities and risks. If you check out the risks
>> that you'll die of various causes, the figures may end up something
>> like this:
>>
>> [snipped table]
>
> Karol:
>> I have seen a similar listing in some book. It placed asteroids in the
>> middle and it was FOLLOWED by plane crashes.
>
> So have I.
usually are car crashes. Riding a plane (or a train) is indeed some
orders of magnitude safer than riding a car.
which probably won't happen until you (and perhaps also your kids,
grandkids and grandgrandkids) are dead already, most people won't
worry about that.
>
> Paul:
>> Statistically, for each asteroid actually impacting the Earth, we can
>> expect about ONE THOUSAND asteroids passing nearer than the Moon but
>> missing the Earth.
>
> Karol:
>> So what? As long as that one in a thousand hits the Earth, the need
>> for means of deflecting it is obvious.
>
> Well, this argument can quickly be deflated by replacing "thousand" with
> "million" or "billion" or "trillion."
distance is some 60 Earth radii, and that number squared is a little
less than 4000 -- not a million, billion, trillion or quadrillion...
> At some point, the risk obviously
> becomes too little to worry about. Nothing in the wording of your
> argument addresses that. Where on your slippery slope do you intend to
> draw the line? And why? That reason for drawing the line where you do,
> *that* is the real argument that you wish to propose.
>
> Once you set down the reason for drawing the line where you do, it should
> be evident why defense can gradually become worth the money to do--it is
> because other risks become relatively smaller against the more or less
> constant risk of asteroid collisions.
scale involved: we've detected perhaps half-a-dozen objects passing
closer to us than the Moon, and most of them have been house-sized
objects which upon impact would produce only local damage.
Statistically, some 4000 of thes ehouse-sized objects woul d have to
pass nearer to the Moon for each such object actually impacting the
Earth. Thus, such an impact is likely to happen only once every
several centuries or so, perhaps once a millennium.
===================================================================
Today's newspaper carried the news that it's a 1 of 300 chance that
the asteroid 1950 DA will collide with the Earth on 16 March 2880.
1950 DA was discovered in 1950, then lost, and finally recovered
in 2000. This prediction was done at Caltech, USA, and is published
today in "Science".
What does this mean? If the 1 in 300 risk is accurate, it means
that out of 300 such predictions, one will yield an actual
collision. It might be this prediction of course, but it probably
isn't.
But it also mean that 1950 DA will, on this date, pass very close
to the Earth - within some 17 Earth radii or less than about 1/4
the distance to the Moon. At such a distance a kilometer-sized
body like 1950 DA will become a naked-eye object, shining at
magnitude 4 to 5 or brighter, depending on how close it actually
gets.
So it's a 1 of 300 risk of a catastrophy, and a 299 of 300 chance
of a splendid celestial show! Later we'll know the odds much more
accurately, and most likely well know if there will be a collosion
or not centuries before 16 March 2880 .... so there's plenty of
time to prepare, if needed.
Karol
> Today's newspaper carried the news that it's a 1 of 300 chance that
> the asteroid 1950 DA will collide with the Earth on 16 March 2880.
> 1950 DA was discovered in 1950, then lost, and finally recovered
> in 2000. This prediction was done at Caltech, USA, and is published
> today in "Science".
>
> What does this mean? If the 1 in 300 risk is accurate, it means
> that out of 300 such predictions, one will yield an actual
> collision. It might be this prediction of course, but it probably
> isn't.
>
> But it also mean that 1950 DA will, on this date, pass very close
> to the Earth - within some 17 Earth radii or less than about 1/4
> the distance to the Moon. At such a distance a kilometer-sized
> body like 1950 DA will become a naked-eye object, shining at
> magnitude 4 to 5 or brighter, depending on how close it actually
> gets.
The news is not that it will hit because it probably won't but that an
improvement in the precision of calculating the ephemeris showed that
we did not know that the object was dangerous even though it was
actually discovered back in 1950. Claiming that we already have or
will be able to chart all objects we really have to worry about is
somehow undermined by 1950 DA's story.
--
Karol
Karol
> > >And there was a comet back in 1997 that went undetected until later
> > >investigations took place because everyone was distracted by H-B's
> > >show.
> >
> > That's sheer hyperbole. The fact is that no survey or group of surveys will
> > ever be 100% effective at detecting all inner solar system objects. Anywhere
> > from 10 to 100 "house-sized" asteroids pass within two lunar orbit radii of
> > Earth during a given year. Astronomers don't miss them because of being
> > distracted. They're missed because they're typically too faint to be detected
> > by current survey instruments.
Oh really, just read this:
"The Comet That Nobody Saw
Professional astronomers and amateurs alike scan the sky continuously,
looking for new, undiscovered objects. But in 1997 they spectacularly
missed a comet tearing through the solar system, says a team that
recorded the comet with a camera aboard the Solar and Heliospheric
Observatory (SOHO). "I'm surprised nobody on the ground actually
discovered [it]," says Brian Marsden of the Harvard-Smithsonian Center
for Astrophysics.
One of SOHO's jobs is to study the solar wind--a giant stream of
particles emitted by the sun--with a wide-angle ultraviolet camera,
called the Solar Wind Anisotropies (SWAN) camera. But SWAN can help
spot comets, too; when a comet approaches the sun, it emits gases,
including hydrogen, that emit ultraviolet light. So Teemu Mäkinen of
the Finnish Meteorological Institute in Helsinki and his colleagues
used SWAN images to catalog all moving objects recorded between
December 1995 and July 1998, after which SOHO temporarily fell silent
(ScienceNOW, 26 June 1998). To their surprise, the researchers found
the tracks of a comet that had previously gone undetected.
SWAN's angular resolution was too low to calculate its orbit.
But the comet ejected water vapor in irregular spurts, which indicates
that it has formed a crust. That suggests it has an elliptical orbit
and regularly skirts the sun, the team reports in the 18 May issue of
Nature.
Mäkinen believes the comet is bright enough to be spotted using
high-power binoculars or a small telescope. "For amateur astronomers,
it would have been an easy object to find," he says. Perhaps it
escaped detection because it approached Earth from behind the sun or
because it moved through the southern sky, which is less well-covered
by systematic comet hunts, he says. But Marsden says the comet may
have been dimmer than the team estimates. Using ultraviolet
observations to calculate a comet's brightness as seen on Earth "may
be a tricky problem," he says.
--Alexander Hellemans"
--
Karol
Sjoplinh
Bugs and rats are the most adaptable species.<< Karol
There are some critters that won't even blink with the biggest (almost)
asteroids...
the underground and deep sea communities that use fossil energy...
chemosythetics, autotrophs, etc.
sj
Paul Schlyter
>
>> In the long run the risk of an asteroidal impact will become
>> significant. The probability that an asteroid impact with more than
>> local damage will occur during the next 100 years is extremely low;
>> the probability it will happen in the next several million years is
>> much much higher.
>
> Please read this:
>
> http://www.spaceflightnow.com/news/n0204/05asteroid/
Please summarize in, say, 10 lines or so of text.
>>>> It's a matter of priorities and risks. If you check out the risks
>>>> that you'll die of various causes, the figures may end up something
>>>> like this:
>>>>
>>>> 50% Heart and lung diseases
>>>> 30% Cancer
>>>> .............................
>>>> 1% Traffic accidents
>>>> 1% Suicide
>>>> 0.5% Other accidents
>>>> 0.2% Volcanic eruptions, floods, storms, etc
>>>> .............................
>>>> 0.0001% Meteor, comet or asteroid impact
>>>> 0.0000001% Nearby nova or supernova
>>>
>>> I have seen a similar listing in some book. It placed asteroids in the
>>> middle and it was FOLLOWED by plane crashes.
>>
>> Plane crashes wasn't included at all in my list here -- with "traffic
>> accidents" I meant mostly car crashes.... <g> Going by plane or
>> train is indeed much safer than going by car - but people still go by
>> car a lot. Why do they do that? Do they want to die? <g>
>
> Plane crashes were on the list I saw in some book.
>>>> Now, what's the point of spending large resources to fight the very
>>>> small risk of a fatal meteor/asteroid impact unless we've first
>>>> eliminated the other, much larger, risks?
>>>
>>> It will not be the statistics that would kill you but the shockwave
>>> and heat followed by nuclear winter and starvation.
>>
>> True, however statistics can tell us the risk of this to happen.
>
> Statistics is often misleading as already mentioned by others.
better than plain guesswork or arguments based on just emotions.
>>> We would be talking a very diffrent way if Tunguska hit Petersburg
>>> instead of Syberia.
>>
>> Also true; however Petersburg is so much much smaller than Siberia
>> that for each Tunguska-sized body hitting Petersburg we could expect
>> thousands of Tunguska-sized bodies hitting Siberia.
>
> Petersburg was on the same latitude as Tunguska. Would the object
> impact a few hours earlier and there would be no Petersburg there and
> a planetary defense system installed in orbit by now.
part, it would have missed the Earth completely, since the Earth
travels its own diameter in its yearly orbit around the Sun in less
than 7 minutes... So you're grossly oversimplifying matters here....
>>> As you have probably noticed after the 2002 EM7 flyby, we cannot
>>> detect Tunguskas at such distances no matter whether the conditions
>>> are favorable or not.
>>
>> If so, how come we know about 2002 EM7 ????? Here you seem to
>> claim we cannot detect it, yet we know about it. How come?
>
> EM7 was detected by accident AFTER it passed its closest point but
> then astronomers calculated where it was earlier.
of NEA's.
> Some people thought
> it was that because it came from the direction where the Sun's glare
> makes observations impossible, but a guy who actually does surveys
> said objects of that size and in that distance are NOT detected at all
> no matter whether the Sun plays a role or not.
so before closest approach, since that would have been too little
time to chang eits path anyway. Path changes of Earth impacting
asteroids must be performed years in advance.
>>> And Tunguska was not so local.
>>
>> Tunguska was barely a regional catastrophy -- it was definitely not a
>> global catastrophy. Many more people are killed by e.g. floods or
>> earthquakes than by meteor/asteroid impacts.
>
> Look at the area where trees were flattened. Now project it on a
> European country.
still "just" a regional catastrophy. If Tunguska had been a global
catastrophy, all of Asia and Europe would have been seriously
damaged -- but that didn't happen.
>>>> Statistically, for each asteroid actually impacting the Earth, we can
>>>> expect about ONE THOUSAND asteroids passing nearer than the Moon but
>>>> missing the Earth.
>>>
>>> So what? As long as that one in a thousand hits the Earth, the need
>>> for means of deflecting it is obvious.
>>
>> You don't get it, do you? Using the current rate of such asteroids
>> passing closer to us than the Moon, please estimate the probable
>> duration until a similar sized asteroid actually hits the Earth.
>> Yep, it will most likely not happen in a very loooooooong time!
>
> Wrong, look at the link I gave you. The fact that it may happen ones
> in a 50 Myrs does not mean it will happen IN 50 Myrs. It may happen
> tomorrow.
more likely to win 1'st prize at a lottery every day for a month or
more.
> And last time actually was 65 Gyrs ago.
>>> The worst thing about asteroids is that we do not know WHEN it
>>> will happen and therefore some people cannot perceive them as a
>>> serius threat.
>>
>> That's nothing unique for asteroids! It's the same with floods,
>> earthquakes, car crashes or diseases: we don't know beforehand
>> WHEN or WHERE they will happen. That's why people don't perceive
>> a car ride as a danger either.....
>
> But we eventually could predict impacts by asteroids
continue.
> and car crashes will always remain unpredictable.
of human behaviour... <g> ....never say never!
>> And you ignore the statistics and assume an almost worst-case
>> scenario for asteroid impacts but not so for other dangers to our
>> lives. That's not a fair comparison...
>
> Ignoring asteroids is not a fair comparison.
BTW in today's paper I read that the asteroid 1950 DA has a 1-in-300
risk of colliding with the Earth in -- 2880 !!!! Yep, that's in
almost 900 years! We've got plenty of time to prepare for that
one....
Karol
> Today's newspaper carried the news that it's a 1 of 300 chance that
> the asteroid 1950 DA will collide with the Earth on 16 March 2880.
> 1950 DA was discovered in 1950, then lost, and finally recovered
> in 2000. This prediction was done at Caltech, USA, and is published
> today in "Science".
And still more reasons to revive Clementine 2:
"TWEAK TEMPERATURES OF SMALLER ASTEROIDS
TO DEFLECT THEM FROM EARTH, UA SCIENTIST SUGGESTS
...Changing how much heat a space rock radiates will change how it
drifts in
its orbit because of the Yarkovsky effect, said Joseph N. Spitale of
the UA
Lunar and Planetary Laboratory in his article, "Asteroid Hazard
Mitigation
Using the Yarkovsky Effect."...
...Spitale said the proposed technique would be useless for a large
asteroid or
an asteroid less than decades away from Earth.
"This technique will work best on objects the size of Golevka or
smaller
(300 meters, about 1,000 feet, or smaller). An object that size could
do
damage to the better part of a country. Even a 100-meter or 50-meter
object
can take out a good part of a city."
"The biggest technical problem right now with this approach is just
doing
the calculations to understand how we'd actually be affecting the
orbit by
doing something to an asteroid surface," Spitale said.
Please note the "affecting the orbit by doing something to an
asteroid's surface" part. Clementine 2 was supposed to do just that
and we won't know until it actually does. We might cover small
asteroids in dirt or paint them white which in my opinion could be as
difficult and as expensive as just nuking them, but the big ones or
the ones detected less than decades before impact must be deflected in
a way Clementine 2 was supposed to test.
--
Karol
Paul Schlyter
>
>> Today's newspaper carried the news that it's a 1 of 300 chance that
>> the asteroid 1950 DA will collide with the Earth on 16 March 2880.
>> 1950 DA was discovered in 1950, then lost, and finally recovered
>> in 2000. This prediction was done at Caltech, USA, and is published
>> today in "Science".
>>
>> What does this mean? If the 1 in 300 risk is accurate, it means
>> that out of 300 such predictions, one will yield an actual
>> collision. It might be this prediction of course, but it probably
>> isn't.
>>
>> But it also mean that 1950 DA will, on this date, pass very close
>> to the Earth - within some 17 Earth radii or less than about 1/4
>> the distance to the Moon. At such a distance a kilometer-sized
>> body like 1950 DA will become a naked-eye object, shining at
>> magnitude 4 to 5 or brighter, depending on how close it actually
>> gets.
>
> The news is not that it will hit because it probably won't
1 chance of 300 it will hit", which is a quite different statement.
> but that an improvement in the precision of calculating the ephemeris
> showed that we did not know that the object was dangerous even though
> it was actually discovered back in 1950.
"discovered in 1950, then lost" -- this means that the observations
of it in 1950 spanned such a short arc that recovery even one year
later was not possible. Quite naturally, one cannot predict the
motion of such an object 800+ years into the future.... Not until
the recovery of this object in 2000 and the subsequent identification
of it being the same as 1950 DA was it possible to predict the close
passage by the Earth in 2880. This was due to the new observations in
2000, and not due to "increased precision in the computations"....
> Claiming that we already have or will be able to chart all objects
> we really have to worry about is somehow undermined by 1950 DA's story.
such a claim, so you're banging in open doors here....
We're talking about probabilities here, not about absolute absence of
danger. No matter how hard we try and whatever anti-impact devices
we build in the future, we will never be able to make the risk of an
asteroid impact exactly zero. As it is, the risk is already
extremely low. So the question is: should we focus on reducing this
already very low risk, or should we focus on reducing other, much
higher, risks for our lives ? You seem to favor to focus on the
low-risk dangers while ignoring the much higher-risk dangers....
Karol
> >> significant. The probability that an asteroid impact with more than
> >> local damage will occur during the next 100 years is extremely low;
> >> the probability it will happen in the next several million years is
> >> much much higher.
> >
> > Please read this:
> >
> > http://www.spaceflightnow.com/news/n0204/05asteroid/
>
> Sorry but I cannot surf the web from here. What does it say?
> Please summarize in, say, 10 lines or so of text.
It says that after improving calculations for an object discovered a
long time ago, namely 1950DA, it turned out that it actually might hit
Earth and not in millions of Earth but in 2880. However, more likely
it will only pass at a 0.25 lunar distance. The news is even
predictions for already known and detected objects, even decades ago,
were not sufficiently accurate to show how dangerous these objects
really are. Humans are far more unwise in this matter than one might
suppose.
> However, statistics isn't ALWAYS misleading! Statistics is usually
> better than plain guesswork or arguments based on just emotions.
Statistics sometimes ARE guesswork and in this case they cannot be
reasonably applied because of the fundamental difference in
statistical factors.
> >>> We would be talking a very diffrent way if Tunguska hit Petersburg
> >>> instead of Syberia.
> >>
> >> Also true; however Petersburg is so much much smaller than Siberia
> >> that for each Tunguska-sized body hitting Petersburg we could expect
> >> thousands of Tunguska-sized bodies hitting Siberia.
> >
> > Petersburg was on the same latitude as Tunguska. Would the object
> > impact a few hours earlier and there would be no Petersburg there and
> > a planetary defense system installed in orbit by now.
>
> If the object had been only 10 minutes ahed of, or behind, its actual
> part, it would have missed the Earth completely, since the Earth
> travels its own diameter in its yearly orbit around the Sun in less
> than 7 minutes... So you're grossly oversimplifying matters here....
OK but it does not change the fact that asteroids are not concious
beings avoiding populated areas and always hitting Syberia. It was
supposed to make you think what would it be like if Tunguska happened
to hit Petersburg instead of trees.
> >>> As you have probably noticed after the 2002 EM7 flyby, we cannot
> >>> detect Tunguskas at such distances no matter whether the conditions
> >>> are favorable or not.
> >>
> >> If so, how come we know about 2002 EM7 ????? Here you seem to
> >> claim we cannot detect it, yet we know about it. How come?
> >
> > EM7 was detected by accident AFTER it passed its closest point but
> > then astronomers calculated where it was earlier.
>
> I know, but it WAS detected, and it will thus enter our statistics
> of NEA's.
And statistics will say we can't detect such objects effectively.
> > Some people thought
> > it was that because it came from the direction where the Sun's glare
> > makes observations impossible, but a guy who actually does surveys
> > said objects of that size and in that distance are NOT detected at all
> > no matter whether the Sun plays a role or not.
>
> However it wouldn't matter whether it had been detected a few days or
> so before closest approach, since that would have been too little
> time to chang eits path anyway. Path changes of Earth impacting
> asteroids must be performed years in advance.
They must be performed years in advance because we have no means of
deflecting them effectively enough. And we don't because we haven't
tested using Clementine 2 what would actually happen after a real
projectile hits a real piece of damn rock but we just look at them and
guess.
> >>> And Tunguska was not so local.
> >>
> >> Tunguska was barely a regional catastrophy -- it was definitely not a
> >> global catastrophy. Many more people are killed by e.g. floods or
> >> earthquakes than by meteor/asteroid impacts.
> >
> > Look at the area where trees were flattened. Now project it on a
> > European country.
>
> So it was perhaps as large as a not-too-large country. That's
> still "just" a regional catastrophy. If Tunguska had been a global
> catastrophy, all of Asia and Europe would have been seriously
> damaged -- but that didn't happen.
It was not global although it did make slight changes to global
climate and such. But we must realise what local really means in this
context: as far as I recall, the area was comparable to Germany.
Having Germany wiped out of the surface and international relations
would cause more havoc than wiping out two towers in NYC. It would be
a WTC event all over the country.
> > Wrong, look at the link I gave you. The fact that it may happen ones
> > in a 50 Myrs does not mean it will happen IN 50 Myrs. It may happen
> > tomorrow.
>
> Yep, it may -- but that's extremely extremely unlikely. You're much
> more likely to win 1'st prize at a lottery every day for a month or
> more.
Everybody could see it is more likely than we think when 1950DA hit
the news yesterday. It would be in a few hundred years and not
millions as you imply.
> > And last time actually was 65 Gyrs ago.
>
> The Earth has existed for only some 5 Gyrs..... <evil grin>
And global extinctions happened more than once.
> >>> The worst thing about asteroids is that we do not know WHEN it
> >>> will happen and therefore some people cannot perceive them as a
> >>> serius threat.
> >>
> >> That's nothing unique for asteroids! It's the same with floods,
> >> earthquakes, car crashes or diseases: we don't know beforehand
> >> WHEN or WHERE they will happen. That's why people don't perceive
> >> a car ride as a danger either.....
> >
> > But we eventually could predict impacts by asteroids
>
> True -- therefore the survey of NEA's should continue. And it will
> continue.
There is no coverage in the southern hemisphere and in the north the
surveys miss 10 mag objects esily picked up by amateurs. And even if
we detect dangerous NEOs we do not even know they are dangerous
because the calcualations lack precision as 1950DA story shows.
> > and car crashes will always remain unpredictable.
>
> :-) ...unless someone is able to produce an accurate computer model
> of human behaviour... <g> ....never say never!
We need an accurate model of asteroid behaviour. But we are not able
to produce it right now and therefore we should learn how to react on
scales better than decades. The impactor won't be so kind to let us
know a few decades in advance.
> >> And you ignore the statistics and assume an almost worst-case
> >> scenario for asteroid impacts but not so for other dangers to our
> >> lives. That's not a fair comparison...
> >
> > Ignoring asteroids is not a fair comparison.
>
> No-one says we shoudl ignore them. We should monitor them for now.
What we really do right now is not far from ignoring. As it turned out
during recent years the surveys are not accurate at all and if there
were no surveys it would not make much of a difference. We will have
to improve them, the sooner the better, but in the mean time we should
test effective weapons since we are unprepared because we do not even
know WHEN to be prepared.
> BTW in today's paper I read that the asteroid 1950 DA has a 1-in-300
> risk of colliding with the Earth in -- 2880 !!!! Yep, that's in
> almost 900 years! We've got plenty of time to prepare for that
> one....
I know, emotions make you wish there was only DA up there but another
news showed there might be TWICE as much asteroids than we thought.
And DA shows it is not a timescale of millions of years you hope for.
--
Karol
Bill Ferris
>I wrote:
>> Karol wrote:
>> >Automated telescopes do not cover sufficient portion of the sky as
>> >already proven by the fact that we still have amateur comet and
>> >asteroid discoveries.
>>
>> The fact that NEOs are discovered by individuals or groups outside the
>> professional surveys is *not* proof that the surveys cover an insufficient
>> portion of the sky. In fact, no survey will ever get every object. Coverage
>in
>
>Yes it is. Amateurs are not as well equipped as those surveys and they
>find bright objects of 10 mag or so. A survey that can miss something
>like that is far from sufficient. And I am not talking "complete
>coverage".
No, it isn't. No survey or can be 100% successful in finding every object. No
matter how many survey scopes we build, objects will still be missed.
Therefore, discoveries by people outside the professional surveys are not
necessarily the result of insufficient sky coverage.
If you want to show that any one or any group of surveys cover "an insufficient
portion of the sky," you need to show a) how much sky needs to be covered each
lunation to meet the goals of the Spaceguard survey; b) how much sky is covered
each lunation; and c) a significant discrepency between what is needed and what
is done. You've done none of this.
>> the northern hemisphere is sufficient, given the performance of LINEAR,
>> LONEOS, Spacewatch, other professional surveys and amateurs involved
>> specifically in asteroid surveys. Coverage in the southern hemisphere is
>> not sufficient. In fact, it's practically non-existent. Too bad Australia
>> decided not to fund a southern hemisphere survey. That wouldn't have
>> completely made up for the deficiency but it would have been a good start.
>
>We've got insufficient coverage in the north and virtually nothing in
>the south. And that means we miss A LOT.
In fact, you have no idea how many objects are missed as a result of not having
Southern Hemisphere surveys.
[edit]
>> You talk about it as though an NEO impact is a foregone conclusion
>> within the next few years or decades. That's just plain wrong.
>
>Just look at the news I linked at the beginning of this post. We DO
>NOT KNOW.
Precisely my point: We don't know. We don't know when the next impactor will
hit. We don't know how much advance warning we'll have. We don't know what its
composition will be. Investing is space-based asteroid defense systems at this
time would be a response based on fear of the unknown. It would be futile.
>> The fact is that we don't know when the next impactor will hit. Analysis of
>> lunar and Earth impact craters suggest something big (1 km or larger) hits
>> Earth every 200,000 to 400,000 years. If you balance the potential loss of
>> human life in such a catastrophic event, the odds of dying in an impact are
>> about equal to those of dying in a plane crash. Now, planes crash every
>> day. Big asteroids hit every 300,000 years or so.
>
>As someone mentioned earlier this is a misconception based on
>confusing average yearly rates of deaths with the real ones.
Where's the misconception in what I wrote? It's an accurate summary of the
situation based on current science.
>> By surveying the larger NEOs, we actually reduce the risk we face
>> from these objects. When we reach that 90% goal, we'll likely be
>> able to say with a fair degree of certainty, "Nine out of ten large
>> potentially hazardous objects are catalogued and not one will hit
>> Earth in the next 100 years."
>>
>> That's quite an effective insurance policy. Much more effective than any
>> space-based defense system.
>
>I would not feel safe if you told me only one bullet out of ten will
>hit me when I go straight under fire.
>--
>Karol
Suppose we were in a house in the middle of a war zone. You have no idea how
many bullets being shot actually come near your house. I say, "Wait a bit and
I'll tell you about how many bullets come near your house." Later, I'm able to
give you a number and add, "And about 4 times an hour, one come pretty near
your door." The unknowns have been reduced. You've got a better idea of the
risk you face when trying to leave the house. But, it's still not enough to
allow you to feel comfortable about walking out the door.
I say, "Wait a bit longer and I'll tell you with near certainty how many
bullets will come near your house in the next hour. Not only that, I'll tell
you which ones will come near your door. And I'll tell you when they'll come
near your door." After I've made good on that promise, you know with near
certainty that no bullets will come near your house or door for the next 15
minutes.
This is essentially what the NEO surveys can provide: knowledge of the objects
which pose a potential threat to Earth, and of any imminent real threat of an
actual impact.
Bill Ferris
because they were distracted by comet Hale-Bopp," Karol wrote:
>Oh really, just read this:
>
>"The Comet That Nobody Saw
>
>Professional astronomers and amateurs alike scan the sky continuously,
>looking for new, undiscovered objects. But in 1997 they spectacularly
>missed a comet ...[edit]
>... Perhaps it escaped detection because it approached Earth from behind
>the sun or because it moved through the southern sky, which is less
>well-covered by systematic comet hunts, he says. But Marsden says the
>comet may have been dimmer than the team estimates. Using ultraviolet
>observations to calculate a comet's brightness as seen on Earth "may
>be a tricky problem," he says.
> --Alexander Hellemans"
Note that among the explanations given for why this comet (C/1997 K2) was not
discovered earlier are the following:
1. The comet approached from behind the Sun
2. The comet moved through the southern sky
3. The comet may have been dimmer than the discovery team estimates.
Nowhere, is it suggested that astronomers were distracted by Hale-Bopp. More
important, note the first item. If the comet was at its brightest while in
conjunction with the Sun, nobody but SOHO would have been able to see it.
Karol
> > The news is not that it will hit because it probably won't
>
> I never claimed the news said "it will hit". The news said "it's
> 1 chance of 300 it will hit", which is a quite different statement.
No Paul, I was not referring to your post but summarizing what the
astronomer said himself:
"However, notes coauthor Steven R. Chesley (JPL), "The impact risk is
not the story here, because we can say almost unequivocally that it's
not going to hit Earth."
My posts have a slight delay when they show up in here so it sometimes
may seem I am referring to some claims that have actually been written
after mine was.
> > but that an improvement in the precision of calculating the ephemeris
> > showed that we did not know that the object was dangerous even though
> > it was actually discovered back in 1950.
>
> Perhaps you should read more carefully before you comment? It was
> "discovered in 1950, then lost" -- this means that the observations
> of it in 1950 spanned such a short arc that recovery even one year
> later was not possible. Quite naturally, one cannot predict the
> motion of such an object 800+ years into the future.... Not until
> the recovery of this object in 2000 and the subsequent identification
> of it being the same as 1950 DA was it possible to predict the close
> passage by the Earth in 2880. This was due to the new observations in
> 2000, and not due to "increased precision in the computations"....
I was not commenting anything but summarizing what the astronomer
said:
"The real story, he says, is how having such a precise orbit has
allowed dynamicists to push the realm of impact prediction so far into
the future. Typically impact probabilities can't be computed reliably
for more than about 100 years in advance, beyond which gravitational
perturbations and other forces make it impossible to predict an
object's exact location. But, Giorginio notes, "Whenever we get radar
data, it opens up a huge window into the future." His team's
900-year-long prognostication was able to include such subtle and
esoteric effects as the Sun's mass loss and galactic tides."
Now I'd like to comment on that. As you can see this WAS due to an
increased precision in the computations made possible by radar
measurements. This method will not be availible for all objects even
in the forseeable future because of lack of funds. And this news came
just a few months after the gov actually wanted to stop funding radar
asteroid measeurements at Arecibo. Therefore we will NOT have
sufficient warnings from surveys and calculating orbits although it is
all getting better. But this should be treated as supplementary
information and it is better to start developing means of deflecting
asteroids as early as possible. We are able to slightly change the
paths of asteroids when they are far away and we know about them
decades in advance, either by using traditional nukes or the Yarkovsky
effect. But because we will NOT know about them decades before impact
but rather months or days if ever, we should be able to do something
about them when they are much closer and that's why we need to finally
test that Clementine 2 thing.
> > Claiming that we already have or will be able to chart all objects
> > we really have to worry about is somehow undermined by 1950 DA's story.
>
> But of course ... and this is obvious. However, no-one ever made
> such a claim, so you're banging in open doors here....
OK I will try to rephrase it: claiming that we do not need Clementine
2 now because we will soon have sufficient (not 100%, but sufficient)
surveys and precise calculations is somehow undermined by 1950DA's
story.
> We're talking about probabilities here, not about absolute absence of
> danger. No matter how hard we try and whatever anti-impact devices
> we build in the future, we will never be able to make the risk of an
> asteroid impact exactly zero. As it is, the risk is already
> extremely low. So the question is: should we focus on reducing this
> already very low risk, or should we focus on reducing other, much
> higher, risks for our lives ? You seem to favor to focus on the
> low-risk dangers while ignoring the much higher-risk dangers....
We have cars with airbags and we are still improving them but we do
virtually nothing to minimise the threat of facing a post-impact era.
Now you tell me, which one is being ignored?
--
Karol
Karol
> >> >Automated telescopes do not cover sufficient portion of the sky as
> >> >already proven by the fact that we still have amateur comet and
> >> >asteroid discoveries.
> >>
> >> The fact that NEOs are discovered by individuals or groups outside the
> >> professional surveys is *not* proof that the surveys cover an insufficient
> >> portion of the sky. In fact, no survey will ever get every object. Coverage
> >in
> >
> >Yes it is. Amateurs are not as well equipped as those surveys and they
> >find bright objects of 10 mag or so. A survey that can miss something
> >like that is far from sufficient. And I am not talking "complete
> >coverage".
>
> No, it isn't. No survey or can be 100% successful in finding every object. No
One of the reasons why we need a Clementine 2 now. Future improvements
in surveys will not eliminate the need completely.
> matter how many survey scopes we build, objects will still be missed.
> Therefore, discoveries by people outside the professional surveys are not
> necessarily the result of insufficient sky coverage.
But not at 10th magnitude brightness level.
> If you want to show that any one or any group of surveys cover "an insufficient
> portion of the sky," you need to show a) how much sky needs to be covered each
> lunation to meet the goals of the Spaceguard survey; b) how much sky is covered
> each lunation; and c) a significant discrepency between what is needed and what
> is done. You've done none of this.
There was no need to because the researchers themselves admit that.
And the surveys are not sufficient due to underfunding.
> >> the northern hemisphere is sufficient, given the performance of LINEAR,
> >> LONEOS, Spacewatch, other professional surveys and amateurs involved
> >> specifically in asteroid surveys. Coverage in the southern hemisphere is
> >> not sufficient. In fact, it's practically non-existent. Too bad Australia
> >> decided not to fund a southern hemisphere survey. That wouldn't have
> >> completely made up for the deficiency but it would have been a good start.
> >
> >We've got insufficient coverage in the north and virtually nothing in
> >the south. And that means we miss A LOT.
>
> In fact, you have no idea how many objects are missed as a result of not having
> Southern Hemisphere surveys.
And that's why we need surveys in the south.
> >> You talk about it as though an NEO impact is a foregone conclusion
> >> within the next few years or decades. That's just plain wrong.
> >
> >Just look at the news I linked at the beginning of this post. We DO
> >NOT KNOW.
>
> Precisely my point: We don't know. We don't know when the next impactor will
> hit. We don't know how much advance warning we'll have. We don't know what its
> composition will be. Investing is space-based asteroid defense systems at this
> time would be a response based on fear of the unknown. It would be futile.
It would be a response based on the fact that accurate predicitons and
warnings will not be availible in the near future and are not
availible now and we need means of reacting effectively even if we do
not get a warning decades in advance.
> >> The fact is that we don't know when the next impactor will hit. Analysis of
> >> lunar and Earth impact craters suggest something big (1 km or larger) hits
> >> Earth every 200,000 to 400,000 years. If you balance the potential loss of
> >> human life in such a catastrophic event, the odds of dying in an impact are
> >> about equal to those of dying in a plane crash. Now, planes crash every
> >> day. Big asteroids hit every 300,000 years or so.
> >
> >As someone mentioned earlier this is a misconception based on
> >confusing average yearly rates of deaths with the real ones.
>
> Where's the misconception in what I wrote? It's an accurate summary of the
> situation based on current science.
Trying to suggest that asteroids are not dangerous because planes
crash everyday and asteroids don't. They really kill when they do,
dinosaurs are far from being alive you know. <jojke>And the dinos
obviously ignored the asteroid threat concerned more with t-rexes
which could kill them "everyday"...</joke> As you can see,
underestimating the danger only because it is less frequent was not a
good idea.
> >> By surveying the larger NEOs, we actually reduce the risk we face
> >> from these objects. When we reach that 90% goal, we'll likely be
> >> able to say with a fair degree of certainty, "Nine out of ten large
> >> potentially hazardous objects are catalogued and not one will hit
> >> Earth in the next 100 years."
> >>
> >> That's quite an effective insurance policy. Much more effective than any
> >> space-based defense system.
> >
> >I would not feel safe if you told me only one bullet out of ten will
> >hit me when I go straight under fire.
> Suppose we were in a house in the middle of a war zone. You have no idea how
> many bullets being shot actually come near your house. I say, "Wait a bit and
> I'll tell you about how many bullets come near your house." Later, I'm able to
> give you a number and add, "And about 4 times an hour, one come pretty near
> your door." The unknowns have been reduced. You've got a better idea of the
> risk you face when trying to leave the house. But, it's still not enough to
> allow you to feel comfortable about walking out the door.
>
> I say, "Wait a bit longer and I'll tell you with near certainty how many
> bullets will come near your house in the next hour. Not only that, I'll tell
> you which ones will come near your door. And I'll tell you when they'll come
> near your door." After I've made good on that promise, you know with near
> certainty that no bullets will come near your house or door for the next 15
> minutes.
>
> This is essentially what the NEO surveys can provide: knowledge of the objects
> which pose a potential threat to Earth, and of any imminent real threat of an
> actual impact.
Your story about the house demonstrated in what why you think about
asteroids. Well, we are NOT inside any house waiting to go out when we
collect enough data to have good warnings. We ARE outside, space is
not some place far away but Earth is IN space. So it is like I am
walking all around with bullets passing by my head all the time and
you tell me not to worry and not to put my bullet-proof clothes on
because "soon" you will be able to tell me of "allmost" every bullet
that might hit me.
---
Karol
Karol
> Attempting to support her claim that astronomers "missed a comet in 1997
> because they were distracted by comet Hale-Bopp," Karol wrote:
>
> >Oh really, just read this:
> >
> >"The Comet That Nobody Saw
> >
> >Professional astronomers and amateurs alike scan the sky continuously,
> >looking for new, undiscovered objects. But in 1997 they spectacularly
> >missed a comet ...[edit]
>
"In the spring and early summer of 1997, stargazers were treated to a
beautiful sky show with the passing of wispy-tailed Comet Hale-Bopp.
But scientists now say that while all eyes were on this dazzling
sight, another near-Earth comet slipped quietly through the sky
unnoticed.
Astronomers analyzing archived data from the European Space
Agency/NASA Solar and Heliospheric Observatory (SOHO) spacecraft have
recently reported the presence of a never-before-detected comet, which
flew close to Earth in 1997. The comet, temporarily dubbed C/1997 K2,
was apparently brighter than every comet discovered by astronomers in
the six months preceding its appearance, adding to the mystery of how
such a prominent comet may have zoomed past Earth unseen.
"To say we were surprised would be a bit of an understatement," said
Finnish astronomer Teemu Mäkinen, lead author of a paper in this
week’s Nature, which describes the new comet discovery. "It
sounded quite unlikely [to us] that a comet of such magnitude could
elude both professionals and amateurs alike."
Despite its brightness, Comet K2 would not have been visible to the
naked eye. Yet even "inexpensive amateur equipment would have
sufficed" for stargazers to see the comet, said Mäkinen. "I believe
that many amateurs were lured by the spectacular display of the
concurrent Comet Hale-Bopp," he explained."
As you can see the lead author himself said that. The article at
space.com that I quote even has a pic with the following caption:
"Bright comets visible in the southern ecliptic hemisphere from May to
July 1997. Arrows depict the movement of comets Hale-Bopp (a), C/1997
N1 Tabur (b), 2p/Encke (c), K2 (d), and C/1997 01 Tilbrook (e).
Courtesy of Nature."
--
Karol
Bill Ferris
The fact is that we don't know when the next impactor will hit. Analysis
of lunar and Earth impact craters suggest something big (1 km or larger)
hits Earth every 200,000 to 400,000 years. If you balance the potential loss
of human life in such a catastrophic event, the odds of dying in an impact
are about equal to those of dying in a plane crash. Now, planes crash every
day. Big asteroids hit every 300,000 years or so.
Karol responded:
[You are] Trying to suggest that asteroids are not dangerous because planes
crash everyday and asteroids don't.
==============
Karol,
It's simply not possible to have reasoned discussion with a person who responds
to statements which were not made. Time to move on.
Paul Schlyter
>>>> In the long run the risk of an asteroidal impact will become
>>>> significant. The probability that an asteroid impact with more than
>>>> local damage will occur during the next 100 years is extremely low;
>>>> the probability it will happen in the next several million years is
>>>> much much higher.
>>>
>>> Please read this:
>>>
>>> http://www.spaceflightnow.com/news/n0204/05asteroid/
>>
>> Sorry but I cannot surf the web from here. What does it say?
>> Please summarize in, say, 10 lines or so of text.
>
> It says that after improving calculations for an object discovered a
> long time ago, namely 1950DA, it turned out that it actually might hit
> Earth and not in millions of Earth but in 2880. However, more likely
> it will only pass at a 0.25 lunar distance. The news is even
> predictions for already known and detected objects, even decades ago,
> were not sufficiently accurate to show how dangerous these objects
> really are. Humans are far more unwise in this matter than one might
> suppose.
Quite naturally we cannot predict their motion in the distant future
since we don't even know where they are NOW! This is not because we
are "unwise" but because we lack data of these objects. And it's
quite wise of us to not pretend we know more than we do, don't you
think so?
>> However, statistics isn't ALWAYS misleading! Statistics is usually
>> better than plain guesswork or arguments based on just emotions.
>
> Statistics sometimes ARE guesswork
better than basing them completely on guesswork....
> and in this case they cannot be reasonably applied because of the
> fundamental difference in statistical factors.
>>>>> We would be talking a very diffrent way if Tunguska hit Petersburg
>>>>> instead of Syberia.
>>>>
>>>> Also true; however Petersburg is so much much smaller than Siberia
>>>> that for each Tunguska-sized body hitting Petersburg we could expect
>>>> thousands of Tunguska-sized bodies hitting Siberia.
>>>
>>> Petersburg was on the same latitude as Tunguska. Would the object
>>> impact a few hours earlier and there would be no Petersburg there and
>>> a planetary defense system installed in orbit by now.
>>
>> If the object had been only 10 minutes ahed of, or behind, its actual
>> part, it would have missed the Earth completely, since the Earth
>> travels its own diameter in its yearly orbit around the Sun in less
>> than 7 minutes... So you're grossly oversimplifying matters here....
>
> OK but it does not change the fact that asteroids are not concious
> beings avoiding populated areas and always hitting Syberia.
are conscious beings.... However all cities of the world occupy only a
small fraction of the total surface area of the world. That's why
an asteroid on a collision course with the Earth has a much large chance
to hit Siberia (or Sahara, or some ocean) than a major city!
> It was supposed to make you think what would it be like if Tunguska
> happened to hit Petersburg instead of trees.
e.g. the damage caused by World Wars 1 and 2 ... and mankind survived
these! Thus, Tunguska was never a threat to mankind -- man himself
poses a greater threat to mankind than asteroid impact of similar
magnitude as Tunguska.
>>>>> As you have probably noticed after the 2002 EM7 flyby, we cannot
>>>>> detect Tunguskas at such distances no matter whether the conditions
>>>>> are favorable or not.
>>>>
>>>> If so, how come we know about 2002 EM7 ????? Here you seem to
>>>> claim we cannot detect it, yet we know about it. How come?
>>>
>>> EM7 was detected by accident AFTER it passed its closest point but
>>> then astronomers calculated where it was earlier.
>>
>> I know, but it WAS detected, and it will thus enter our statistics
>> of NEA's.
>
> And statistics will say we can't detect such objects effectively.
The efficiency factor here would me:
no_of_detected_NEAs
------------------------------------------------
no_of_detected_NEAs + no_of_undetected_NEAs
Quite naturally, the quantity no_of_undetected_NEAs is unknown. So this
is an example of guesswork, not statistics....
Also you said "statistics will say" --- do you think you can predict the
future, or what?
>>> Some people thought
>>> it was that because it came from the direction where the Sun's glare
>>> makes observations impossible, but a guy who actually does surveys
>>> said objects of that size and in that distance are NOT detected at all
>>> no matter whether the Sun plays a role or not.
>>
>> However it wouldn't matter whether it had been detected a few days or
>> so before closest approach, since that would have been too little
>> time to chang eits path anyway. Path changes of Earth impacting
>> asteroids must be performed years in advance.
>
> They must be performed years in advance because we have no means of
> deflecting them effectively enough. And we don't because we haven't
> tested using Clementine 2 what would actually happen after a real
> projectile hits a real piece of damn rock but we just look at them and
> guess.
bodies... <g>
>>>>> And Tunguska was not so local.
>>>>
>>>> Tunguska was barely a regional catastrophy -- it was definitely not a
>>>> global catastrophy. Many more people are killed by e.g. floods or
>>>> earthquakes than by meteor/asteroid impacts.
>>>
>>> Look at the area where trees were flattened. Now project it on a
>>> European country.
>>
>> So it was perhaps as large as a not-too-large country. That's
>> still "just" a regional catastrophy. If Tunguska had been a global
>> catastrophy, all of Asia and Europe would have been seriously
>> damaged -- but that didn't happen.
>
> It was not global although it did make slight changes to global
> climate
atmosphere, perhaps as much as a major volcanic eruption. But I've
never heard of any lasting climatic effect from Tunguska -- and since
it happened soon 100 years ago, there's enough statistics to cover
that if it did happen.
> and such.
What do you meah with "as such" here? Please be more specific.
> But we must realise what local really means in this
> context: as far as I recall, the area was comparable to Germany.
> Having Germany wiped out of the surface and international relations
> would cause more havoc than wiping out two towers in NYC. It would be
> a WTC event all over the country.
DELIBERATE ACTIONS BY PEOPLE. It was not a natural catastrophy, and
that's why we now have a lot of increased safety measures here and
there. If we count the number of dead only, that number in the WTC
catastrophy wasn't larger than in e.g. the large earthquake in
western Turkey a little more than 2 years earlier.
"Having Germany wiped out" -- isn't that pretty much what happened
during the end of WW II? Mankind, and even Germany, survived that...
The "advantage" of a natural catastrophy here (as opposed to wars or
terrorist actions) is that it won't have any political implications.
Germany wasn't "only" almost wiped out during the end of WW II, it
was also divided into two countries for almost 50 years afterwards.
>>> Wrong, look at the link I gave you. The fact that it may happen ones
>>> in a 50 Myrs does not mean it will happen IN 50 Myrs. It may happen
>>> tomorrow.
>>
>> Yep, it may -- but that's extremely extremely unlikely. You're much
>> more likely to win 1'st prize at a lottery every day for a month or
>> more.
>
> Everybody could see it is more likely than we think when 1950DA hit
> the news yesterday.
than YOU thought before 1950 DA hit the news yesterday? Different
people think differently. However what we "think" matters little
here -- more important is what we KNOW....
> It would be in a few hundred years and not millions as you imply.
wasn't a prediction of an impact -- now you argue as if the impact
was a fact rather than a mere 1 chance of 300.
Now, if there's 1 chance of 300 of an asteroid impact every 1000 years
or so, this means it'll be an actual impact every 300,000 years or
so -- right?
>>> And last time actually was 65 Gyrs ago.
>>
>> The Earth has existed for only some 5 Gyrs..... <evil grin>
>
> And global extinctions happened more than once.
But you probably meant 65 Myrs rather than 65 Gyrs, didn't you?
Be careful with those prefixes.....
>>>>> The worst thing about asteroids is that we do not know WHEN it
>>>>> will happen and therefore some people cannot perceive them as a
>>>>> serius threat.
>>>>
>>>> That's nothing unique for asteroids! It's the same with floods,
>>>> earthquakes, car crashes or diseases: we don't know beforehand
>>>> WHEN or WHERE they will happen. That's why people don't perceive
>>>> a car ride as a danger either.....
>>>
>>> But we eventually could predict impacts by asteroids
>>
>> True -- therefore the survey of NEA's should continue. And it will
>> continue.
>
> There is no coverage in the southern hemisphere
southern skies forever. Eventually they'll move up into the northern
skies.
> and in the north the surveys miss 10 mag objects esily picked up by
> amateurs.
"easily" picked up by amateurs, as you here claim, then amateurs
ought to be able to successfully run their own NEA program, right?
And you could become one of them. So why don't you get an amateur
telescope, then move to the southern hemisphere and save the world
from destruction by discovering Earth-impacting NEA's which otherwise
would remain undetected until impact? If you do this, you'll make it
into the history books - wouldn't that be something?
> And even if we detect dangerous NEOs we do not even know they are
> dangerous because the calcualations lack precision as 1950DA story shows.
such program. Today much fewer asteroids are lost, and a lot of
previously lost asteroids are recovered. If the NEA program is run
for another century or so, at some point the number of newly detected
NEA's will probably decline sharply -- when this happens, it will be
a clear indication that we've discovered almost all NEA's.
>>> and car crashes will always remain unpredictable.
>>
>> :-) ...unless someone is able to produce an accurate computer model
>> of human behaviour... <g> ....never say never!
>
> We need an accurate model of asteroid behaviour. But we are not able
> to produce it right now and therefore we should learn how to react on
> scales better than decades. The impactor won't be so kind to let us
> know a few decades in advance.
in advance.....
>>>> And you ignore the statistics and assume an almost worst-case
>>>> scenario for asteroid impacts but not so for other dangers to our
>>>> lives. That's not a fair comparison...
>>>
>>> Ignoring asteroids is not a fair comparison.
>>
>> No-one says we shoudl ignore them. We should monitor them for now.
>
> What we really do right now is not far from ignoring.
southern hemisphere and save the world by discovering those asteroids
everyone else ignores? Earlier you said amateurs could "easily" do
this. Now, if you believe your own claims, what are you waiting for?
Get going! Or do you really want to die? <grin>
> As it turned out during recent years the surveys are not accurate
> at all and if there were no surveys it would not make much of a
> difference.
> We will have to improve them, the sooner the better, but in the mean
> time we should test effective weapons since we are unprepared because
> we do not even know WHEN to be prepared.
need to be prepared?
>> BTW in today's paper I read that the asteroid 1950 DA has a 1-in-300
>> risk of colliding with the Earth in -- 2880 !!!! Yep, that's in
>> almost 900 years! We've got plenty of time to prepare for that
>> one....
>
> I know, emotions make you wish there was only DA up there but another
> news showed there might be TWICE as much asteroids than we thought.
> And DA shows it is not a timescale of millions of years you hope for.
million years, so it's still a time scale of the order of magnitude
of a million years. And even if there was TWICE as many asteroids as
we thought, we most likely still have plenty of time.
First we should survey as many NEA's as we can. When we've
encountered a case with a known, or highly probable, Earth impact,
THEN it's time to prepare counteractions. It took only 8 years to
prepare for the manned moon landings (from the Kennedy speach to the
actual first landing). Preparing a mission to deflect an asteroid is
probably easire, since it won't have to be manned.
Paul Schlyter
>
>>> The news is not that it will hit because it probably won't
>>
>> I never claimed the news said "it will hit". The news said "it's
>> 1 chance of 300 it will hit", which is a quite different statement.
>
> No Paul, I was not referring to your post
clarification......
> I was not commenting anything but summarizing what the astronomer
> said:
this..... <evil grin> ....as you may not know, "The Astronomer"
is a magazine devoted to observational astronomy....
> "The real story, he says, is how having such a precise orbit has
> allowed dynamicists to push the realm of impact prediction so far into
> the future. Typically impact probabilities can't be computed reliably
> for more than about 100 years in advance, beyond which gravitational
> perturbations and other forces make it impossible to predict an
> object's exact location. But, Giorginio notes, "Whenever we get radar
> data, it opens up a huge window into the future." His team's
> 900-year-long prognostication was able to include such subtle and
> esoteric effects as the Sun's mass loss and galactic tides."
>
> Now I'd like to comment on that. As you can see this WAS due to an
> increased precision in the computations made possible by radar
> measurements.
_accuracy_ in the final result, due to an increased accuracy in the
input data! The precision was probably enough both before and after
these radar measurements: nowadays double precision (14 to 16 decimal
digits) is standard and quad precision (about 30 decimal digits) is
often used in these computations. Getting an inaccurate result just
because of too little precision in the computations is an
unforgiveable error which usually only beginning computors commit.
However, it's sufficient to be able to predict these impacts 100
years in advance; 880 years is a luxury here, and we'll probably
see MANY refined predicitions before the year 2880 ....
> This method will not be availible for all objects even
> in the forseeable future because of lack of funds. And this news came
> just a few months after the gov actually wanted to stop funding radar
> asteroid measeurements at Arecibo. Therefore we will NOT have
> sufficient warnings from surveys and calculating orbits although it is
> all getting better.
Think back 100 years, to the year 1902! Back then, the world's
largest telescope was still Lord Rosse's "Leviathan" (Mt Wilson
wasn't opened unti 1904, and the Hooker telescope wasn't operational
until 1917). Space travel was science fiction, and only a few
hundred asteroids were known, and the only NEA known was Eros.
We've come a long way since 1902. Now, suppose the news reached us
that a kilometer sized asteroid would hit the Earth in, say, 2102.
Do you really think that would be insufficient time to do our best to
try to avoid that impact? Don't you think a lot will happen during
the next 100 years as well?
> But this should be treated as supplementary
> information and it is better to start developing means of deflecting
> asteroids as early as possible. We are able to slightly change the
> paths of asteroids when they are far away and we know about them
> decades in advance, either by using traditional nukes or the Yarkovsky
> effect. But because we will NOT know about them decades before impact
> but rather months or days if ever, we should be able to do something
> about them when they are much closer and that's why we need to finally
> test that Clementine 2 thing.
decades in advance. If we get to know about it only months in
advance, it will be too late.
>>> Claiming that we already have or will be able to chart all objects
>>> we really have to worry about is somehow undermined by 1950 DA's story.
>>
>> But of course ... and this is obvious. However, no-one ever made
>> such a claim, so you're banging in open doors here....
>
> OK I will try to rephrase it: claiming that we do not need Clementine
> 2 now because we will soon have sufficient (not 100%, but sufficient)
> surveys and precise calculations is somehow undermined by 1950DA's
> story.
advance is insufficient time to prepare for it? I strongly
disagree... Even if we learnt about it as "little" as 100 years in
advance that would be plenty of time. We'd probably do fine if we
learnt it 20 or so years in advance -- after all it took only 8 years
from JFK's speech of the manned lunar landing until man actually set
foot on the moon. If knowledge about a future asteroid impact would
appear, that ought to produce an equally strong motivation....
>> We're talking about probabilities here, not about absolute absence of
>> danger. No matter how hard we try and whatever anti-impact devices
>> we build in the future, we will never be able to make the risk of an
>> asteroid impact exactly zero. As it is, the risk is already
>> extremely low. So the question is: should we focus on reducing this
>> already very low risk, or should we focus on reducing other, much
>> higher, risks for our lives ? You seem to favor to focus on the
>> low-risk dangers while ignoring the much higher-risk dangers....
>
> We have cars with airbags and we are still improving them but we do
> virtually nothing to minimise the threat of facing a post-impact era.
> Now you tell me, which one is being ignored?
how many people die due to asteroid impacts each year, if we average
it over the last 200 years or so? Feel free to assume that the
Tunguska meteor actually did hit S:t Petersburg if you like.....
some 100 years ago, S:t Petersburg perhaps had 1 million or so
people. Divide that by 200 and you'll get 5000 people/year on the
average, compared to the millions per year which now die in car
crashes...
Karol
> However, it's sufficient to be able to predict these impacts 100
> years in advance; 880 years is a luxury here, and we'll probably
> see MANY refined predicitions before the year 2880 ....
I think the news here is that when we get the luxury of high-precision
radar data, it suddenly turns out that there are lots of potential
impactors that we are unaware in spite of the fact that we have
already discovered them. The next logical step would be to obtain
radar data for all known asteroids and those newly discovered ones.
But we won't because of the lack of funds. Therefore we must have
means to deflect asteroids if we get a warning months before impact
and not decades.
> Our only chance is to get to know about these impacts years or preferably
> decades in advance. If we get to know about it only months in
> advance, it will be too late.
And that's why we need Clementine 2.
> > OK I will try to rephrase it: claiming that we do not need Clementine
> > 2 now because we will soon have sufficient (not 100%, but sufficient)
> > surveys and precise calculations is somehow undermined by 1950DA's
> > story.
>
> So you claim that knowledge about the risk of an impact 878 years in
> advance is insufficient time to prepare for it? I strongly
> disagree... Even if we learnt about it as "little" as 100 years in
> advance that would be plenty of time. We'd probably do fine if we
> learnt it 20 or so years in advance -- after all it took only 8 years
> from JFK's speech of the manned lunar landing until man actually set
> foot on the moon. If knowledge about a future asteroid impact would
> appear, that ought to produce an equally strong motivation....
No I claim that we will not have warnings decades before impacts
because accurate predictions are only possible using radars as shown
above. And because we cannot fung appropriate radar research we have
to start developing the technology now. Progress is not made by
itself. We have to start the tests now to have a reliable planetary
defense system in the future.
> Millions of people die in car accidents each year, worldwide. Now,
> how many people die due to asteroid impacts each year, if we average
> it over the last 200 years or so? Feel free to assume that the
> Tunguska meteor actually did hit S:t Petersburg if you like.....
> some 100 years ago, S:t Petersburg perhaps had 1 million or so
> people. Divide that by 200 and you'll get 5000 people/year on the
> average, compared to the millions per year which now die in car
> crashes...
Averaging the millions over long timescales is just what i find
misleading when using statistics with asteroids.
--
Karol
Karol
> I wrote:
> The fact is that we don't know when the next impactor will hit. Analysis
> of lunar and Earth impact craters suggest something big (1 km or larger)
> hits Earth every 200,000 to 400,000 years. If you balance the potential loss
> of human life in such a catastrophic event, the odds of dying in an impact
> are about equal to those of dying in a plane crash. Now, planes crash every
> day. Big asteroids hit every 300,000 years or so.
>
> Karol responded:
> [You are] Trying to suggest that asteroids are not dangerous because planes
> crash everyday and asteroids don't.
>
> to statements which were not made. Time to move on.
You put the [You are] part in. Not me. So who's responding to
nonexistent statements? I noticed this group is infested with kooks as
never before. They are never sure what they want and will never
reasonably respond to contradictory arguments. Well I am an amateur
astronomer from Poland and you can visit my club's homepage if you
wish to check it. And I am sure what I want: I would like to take into
consideration reviving the project of Clementine 2 spacecraft. I
needed your help in evaluating the urgency and feasiblity of doing
that. Some people have presented specific facts. Others just keep on
saying we just do not have to worry about asteroids.
--
Karol
Thad Floryan
| [...]
| The big asteroid hit, however, is much more like the "5 billion people
| every 15 million years" event than the other. This produces a tremendous
| skew in the death count distribution, over a period as small as a year,
| or even a person's lifetime. In 14,999,999 out of every 15,000,000 years,
| nothing. That one year, everybody (or most everybody) dies.
|
| I've found that the reaction of people to such a skewed risk varies
| enormously. Some people look at the huge time spans involved, ignoring
| the equally huge death tolls, and say, "Eh, what's to worry about?"
| Others look at it exactly the other way, and respond accordingly. We
| don't really understand very well how we should address this kind of
| risk.
The Tunguska event was in 1908 (only 96 years ago), and the Carolina Bays
"seems to be" about 10,500 years ago based on erosion, etc. If you didn't
read the report whose URL I previously posted, the Carolina Bays comprise
500,000+ craters ranging from 200 feet to over 7 miles and covering the
entire USA Atlantic seacoast from New Jersey to Florida (with the remainder
probably in the ocean) -- this was truly a cataclysmic event occuring in
relatively recent time. The 1995 article in ASTRONOMY mentioned a number of
recent grazers, and let's not forget the Shoemaker-Levy Jupiter bombardment
of 1994.
Mark Twain (aka Samuel Clemens) wrote (paraphrased), "there are lies, then
there are damned lies, and then there are statistics."
Stuff happens. And it's clear we (humankind) are not presently prepared
to avert such a disaster (a comet, asteroid, or meteor strike).
Thad Floryan
| [...]
| My point in bringing this number up is to again point at the time
| scale involved: we've detected perhaps half-a-dozen objects passing
| closer to us than the Moon, and most of them have been house-sized
| objects which upon impact would produce only local damage.
| Statistically, some 4000 of thes ehouse-sized objects woul d have to
| pass nearer to the Moon for each such object actually impacting the
| Earth. Thus, such an impact is likely to happen only once every
| several centuries or so, perhaps once a millennium.
Statistics mean NOTHING in the grand scheme of things. Consider how
many NEOs aren't discovered until after the fact.
All it's gonna take is some new comet popping out of the OORT and heading
towards Earth.
| Today's newspaper carried the news that it's a 1 of 300 chance that
| the asteroid 1950 DA will collide with the Earth on 16 March 2880.
| [...]
| So it's a 1 of 300 risk of a catastrophy, and a 299 of 300 chance
| of a splendid celestial show! Later we'll know the odds much more
| accurately, and most likely well know if there will be a collosion
| or not centuries before 16 March 2880 .... so there's plenty of
| time to prepare, if needed.
But what about the as-yet undiscovered objects with Earth in their paths?
Suppose there's some comet in an otherwise benign orbit which perturbs some
other objects, say, asteroids, and sends them hurtling towards the Earth.
Stuff happens.
Brian Tung
> The Tunguska event was in 1908 (only 96 years ago), and the Carolina Bays
> "seems to be" about 10,500 years ago based on erosion, etc. If you didn't
> read the report whose URL I previously posted, the Carolina Bays comprise
> 500,000+ craters ranging from 200 feet to over 7 miles and covering the
> entire USA Atlantic seacoast from New Jersey to Florida (with the remainder
> probably in the ocean) -- this was truly a cataclysmic event occuring in
> relatively recent time. The 1995 article in ASTRONOMY mentioned a number of
> recent grazers, and let's not forget the Shoemaker-Levy Jupiter bombardment
> of 1994.
Not to put too fine a point on it, the Tunguska event did not destroy
human life outside a relatively limited radius, nor did it did even
destroy life in general outside a relatively limited radius. To be
sure, if it had hit St Petersburg, or Moscow, or London, or New York,
the devastation would have been cataclysmic--but for those areas, not
for human life (or even for human civilization).
Nor is there any evidence that the Carolina Bays events, as destructive
as they may have been, did anything to clear out human life. They may
have done quite a number on civilization (and there are simply many more
humans available for killing now than there were 10,500 years ago), but
those are not the impacts I was talking about.
When I spoke of "the big one," I didn't mean to imply that there are
either big ones or meteor showers. Naturally, there is a continuum of
impactors. But my eventual point was about people's assessment of
stochastic events when those events are not a complete order.
> Mark Twain (aka Samuel Clemens) wrote (paraphrased), "there are lies, then
> there are damned lies, and then there are statistics."
>
> Stuff happens. And it's clear we (humankind) are not presently prepared
> to avert such a disaster (a comet, asteroid, or meteor strike).
We are not prepared to avert many disasters. That's not the question at
issue--whether *this* disaster should be high on our list of priorities,
however, is.
Brian Tung <br...@isi.edu>
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt
Karol
> There are lots of asteroids which were discovered and then lost.
> Quite naturally we cannot predict their motion in the distant future
> since we don't even know where they are NOW! This is not because we
> are "unwise" but because we lack data of these objects. And it's
> quite wise of us to not pretend we know more than we do, don't you
> think so?
OK what I meant was we kind of ARE pretending we know more that we do
because we strongly believe we will have warnings decades before
impact. But this would be possible if all NEOs were measured by radar
which is not possible.
> >> However, statistics isn't ALWAYS misleading! Statistics is usually
> >> better than plain guesswork or arguments based on just emotions.
> >
> > Statistics sometimes ARE guesswork
>
> Even if so, basing your conclusions partially on guesswork is still
> better than basing them completely on guesswork....
>
> > and in this case they cannot be reasonably applied because of the
> > fundamental difference in statistical factors.
>
> What "fundamental difference"? Please elaborate....
Averaging the asteroids causalties factor over long periods and
comparing them with car accidents is like comparing really
incompatible things. It looks like a basic statistical misconception
to me. If you think different, please tell me why.
> >> If the object had been only 10 minutes ahed of, or behind, its actual
> >> part, it would have missed the Earth completely, since the Earth
> >> travels its own diameter in its yearly orbit around the Sun in less
> >> than 7 minutes... So you're grossly oversimplifying matters here....
> >
> > OK but it does not change the fact that asteroids are not concious
> > beings avoiding populated areas and always hitting Syberia.
>
> Again you're beating in open doors! No-one has evern claimed asteroids
> are conscious beings.... However all cities of the world occupy only a
> small fraction of the total surface area of the world. That's why
> an asteroid on a collision course with the Earth has a much large chance
> to hit Siberia (or Sahara, or some ocean) than a major city!
Yes but we tend to count on good luck. I think it has saved us many
times. But it is high time we were able to REALLY do something more
than just pray.
> > It was supposed to make you think what would it be like if Tunguska
> > happened to hit Petersburg instead of trees.
>
> Even if that had happened, the damage would be considerably less than
> e.g. the damage caused by World Wars 1 and 2 ... and mankind survived
> these! Thus, Tunguska was never a threat to mankind -- man himself
> poses a greater threat to mankind than asteroid impact of similar
> magnitude as Tunguska.
WTC was nothing compared to WW1 and WW2 and yet people did consider it
a major loss.
> >>>>> As you have probably noticed after the 2002 EM7 flyby, we cannot
> >>>>> detect Tunguskas at such distances no matter whether the conditions
> >>>>> are favorable or not.
> >>>>
> >>>> If so, how come we know about 2002 EM7 ????? Here you seem to
> >>>> claim we cannot detect it, yet we know about it. How come?
> >>>
> >>> EM7 was detected by accident AFTER it passed its closest point but
> >>> then astronomers calculated where it was earlier.
> >>
> >> I know, but it WAS detected, and it will thus enter our statistics
> >> of NEA's.
> >
> > And statistics will say we can't detect such objects effectively.
>
> WHAT statistics?
>
> The efficiency factor here would me:
>
> no_of_detected_NEAs
> ------------------------------------------------
> no_of_detected_NEAs + no_of_undetected_NEAs
>
> Quite naturally, the quantity no_of_undetected_NEAs is unknown. So this
> is an example of guesswork, not statistics....
You said about putting EM7 into statistics not me.
> Also you said "statistics will say" --- do you think you can predict the
> future, or what?
No I am not another fancy kook infesting this group.
> >> However it wouldn't matter whether it had been detected a few days or
> >> so before closest approach, since that would have been too little
> >> time to chang eits path anyway. Path changes of Earth impacting
> >> asteroids must be performed years in advance.
> >
> > They must be performed years in advance because we have no means of
> > deflecting them effectively enough. And we don't because we haven't
> > tested using Clementine 2 what would actually happen after a real
> > projectile hits a real piece of damn rock but we just look at them and
> > guess.
>
> Sorry but I don't see how Clementine 2 could help in detecting these
> bodies... <g>
Sorry but I never claimed it would help in detecting them. I just
think some means of deflecting asteroids even when they are not
detected decades prior to impact would be really nice when we are
almost sure we cannot have warnings decades before impact because what
we do never has apprioperate funds and is therefore never reliable
enough.
> > It was not global although it did make slight changes to global
> > climate
>
> I don't think so. Yes it did eject a fair amount of dust in the
> atmosphere, perhaps as much as a major volcanic eruption. But I've
> never heard of any lasting climatic effect from Tunguska -- and since
> it happened soon 100 years ago, there's enough statistics to cover
> that if it did happen.
>
> > and such.
>
> What do you meah with "as such" here? Please be more specific.
The effects of the impact were observed in Europe. One could read a
newspaper after midnight because of the "fair amount of dust"
reflecting sunlight. I guess there could be some slight variations in
climate after even the small impacts but that is not the main point.
> > But we must realise what local really means in this
> > context: as far as I recall, the area was comparable to Germany.
> > Having Germany wiped out of the surface and international relations
> > would cause more havoc than wiping out two towers in NYC. It would be
> > a WTC event all over the country.
>
> The major thing about the WTC catastrophy was that it was caused by
> DELIBERATE ACTIONS BY PEOPLE. It was not a natural catastrophy, and
> that's why we now have a lot of increased safety measures here and
> there. If we count the number of dead only, that number in the WTC
> catastrophy wasn't larger than in e.g. the large earthquake in
> western Turkey a little more than 2 years earlier.
>
> "Having Germany wiped out" -- isn't that pretty much what happened
> during the end of WW II? Mankind, and even Germany, survived that...
> The "advantage" of a natural catastrophy here (as opposed to wars or
> terrorist actions) is that it won't have any political implications.
> Germany wasn't "only" almost wiped out during the end of WW II, it
> was also divided into two countries for almost 50 years afterwards.
"After WWII" was before globalisation was complete. Now Germany is
strongly involved in global relations as all major countries. If
Germany, Spain, France or UK were suddenly wiped out by a Tunguska, it
would have major implications for decades to follow.
> > It would be in a few hundred years and not millions as you imply.
>
> Now you're contradicting yourself! Earlier you correctly said this
> wasn't a prediction of an impact -- now you argue as if the impact
> was a fact rather than a mere 1 chance of 300.
>
> Now, if there's 1 chance of 300 of an asteroid impact every 1000 years
> or so, this means it'll be an actual impact every 300,000 years or
> so -- right?
Wrong, there probably will be NO impact in 2880 but this showed as a
general pattern that frequency of 1 in 300,000 years does not
necessairily mean it will happen IN 300,000 but might be MUCH earlier
- in a hundred years or next year - we just don't know. But we cannot
say that we do not have to worry because it won't happen until another
300,000 years pass.
> >>> And last time actually was 65 Gyrs ago.
> >>
> >> The Earth has existed for only some 5 Gyrs..... <evil grin>
> >
> > And global extinctions happened more than once.
>
> ... i.e. they weren't really extinctions since life survived.... <g>
> But you probably meant 65 Myrs rather than 65 Gyrs, didn't you?
> Be careful with those prefixes.....
Yeap, thanks. I meant Myrs. I sometimes get confused with these since
I am not a native English speaker. And if we call killing dinosaurs a
global extinction, there were some before the dinos and another one is
likely to happen.
> > There is no coverage in the southern hemisphere
>
> Doesn't matter much because no asteroid will remain in the far
> southern skies forever. Eventually they'll move up into the northern
> skies.
Does matter because we might miss a lot of potential future impactors
due to this. It is more a matter of favorable conditions.
> > and in the north the surveys miss 10 mag objects esily picked up by
> > amateurs.
>
> ALL such objects or only SOME of them? Also, if these objects are
> "easily" picked up by amateurs, as you here claim, then amateurs
> ought to be able to successfully run their own NEA program, right?
> And you could become one of them. So why don't you get an amateur
> telescope, then move to the southern hemisphere and save the world
> from destruction by discovering Earth-impacting NEA's which otherwise
> would remain undetected until impact? If you do this, you'll make it
> into the history books - wouldn't that be something?
I live in Poland and have not much prospects of moving south. Amateurs
are able to pick SOME of the objects that surveys have missed. I would
feel better if the surveys did not miss 10 mag comets.
> > And even if we detect dangerous NEOs we do not even know they are
> > dangerous because the calcualations lack precision as 1950DA story shows.
>
> The NEA program is only about a decade old -- in 1950 there was no
> such program. Today much fewer asteroids are lost, and a lot of
> previously lost asteroids are recovered. If the NEA program is run
> for another century or so, at some point the number of newly detected
> NEA's will probably decline sharply -- when this happens, it will be
> a clear indication that we've discovered almost all NEA's.
But the slow improvement of surveys may be disturbed by an actual
impact <evil grin>
> > We need an accurate model of asteroid behaviour. But we are not able
> > to produce it right now and therefore we should learn how to react on
> > scales better than decades. The impactor won't be so kind to let us
> > know a few decades in advance.
>
> 1950DA was kind enough to let us know about such a risk almost 900 years
> in advance.....
Only because we had excellent radar data and we usually don't.
> > What we really do right now is not far from ignoring.
>
> If so, why don't you get an amateur telescope, and then move to the
> southern hemisphere and save the world by discovering those asteroids
> everyone else ignores? Earlier you said amateurs could "easily" do
> this. Now, if you believe your own claims, what are you waiting for?
> Get going! Or do you really want to die? <grin>
No I don't and if I had enough cash I would move from Poland and do
exactly what you say. I would even set up my own NEAT, LONEOS or
LINEAR in the south if I could.
> > As it turned out during recent years the surveys are not accurate
> > at all and if there were no surveys it would not make much of a
> > difference.
>
> WHo made this conclusion, and where and when?
Me, in Poland, a few days ago - after 1950 DA news <grin> DA showed us
what getting the measurements SHOULD look like and the gov always
shows as they will NEVER be possible cause funding war is more
important than saving people.
> > We will have to improve them, the sooner the better, but in the mean
> > time we should test effective weapons since we are unprepared because
> > we do not even know WHEN to be prepared.
>
> WHat's the point of preparing yourself if you have no idea WHEN you
> need to be prepared?
If you told me I live in a dangerous neighbourhood and may be hurt any
moment I WOULD buy a gun although I would not know WHEN EXACTLY when
it will happen.
> >> BTW in today's paper I read that the asteroid 1950 DA has a 1-in-300
> >> risk of colliding with the Earth in -- 2880 !!!! Yep, that's in
> >> almost 900 years! We've got plenty of time to prepare for that
> >> one....
> >
> > I know, emotions make you wish there was only DA up there but another
> > news showed there might be TWICE as much asteroids than we thought.
> > And DA shows it is not a timescale of millions of years you hope for.
>
> 300 times 900 years is 270,000 years, i.e. about a quarter of a
> million years, so it's still a time scale of the order of magnitude
> of a million years. And even if there was TWICE as many asteroids as
> we thought, we most likely still have plenty of time.
Your calculations are right only if there were only objects like DA
and you know that.
> First we should survey as many NEA's as we can. When we've
> encountered a case with a known, or highly probable, Earth impact,
> THEN it's time to prepare counteractions. It took only 8 years to
> prepare for the manned moon landings (from the Kennedy speach to the
> actual first landing). Preparing a mission to deflect an asteroid is
> probably easire, since it won't have to be manned.
It would be much easier and much faster if we did some tests before we
actually start developing a planetary defense system because we may
suddenly face some technical difficulties and it might be too late
then.
--
Karol
Karol
> There are lots of asteroids which were discovered and then lost.
> Quite naturally we cannot predict their motion in the distant future
> since we don't even know where they are NOW! This is not because we
> are "unwise" but because we lack data of these objects. And it's
> quite wise of us to not pretend we know more than we do, don't you
> think so?
OK what I meant was we kind of ARE pretending we know more that we do
because we strongly believe we will have warnings decades before
impact. But this would be possible if all NEOs were measured by radar
which is not possible.
> >> However, statistics isn't ALWAYS misleading! Statistics is usually
> >> better than plain guesswork or arguments based on just emotions.
> >
> > Statistics sometimes ARE guesswork
>
> Even if so, basing your conclusions partially on guesswork is still
> better than basing them completely on guesswork....
>
> > and in this case they cannot be reasonably applied because of the
> > fundamental difference in statistical factors.
>
> What "fundamental difference"? Please elaborate....
Averaging the asteroids causalties factor over long periods and
comparing them with car accidents is like comparing really
incompatible things. It looks like a basic statistical misconception
to me. If you think different, please tell me why.
> >> If the object had been only 10 minutes ahed of, or behind, its actual
> >> part, it would have missed the Earth completely, since the Earth
> >> travels its own diameter in its yearly orbit around the Sun in less
> >> than 7 minutes... So you're grossly oversimplifying matters here....
> >
> > OK but it does not change the fact that asteroids are not concious
> > beings avoiding populated areas and always hitting Syberia.
>
> Again you're beating in open doors! No-one has evern claimed asteroids
> are conscious beings.... However all cities of the world occupy only a
> small fraction of the total surface area of the world. That's why
> an asteroid on a collision course with the Earth has a much large chance
> to hit Siberia (or Sahara, or some ocean) than a major city!
Yes but we tend to count on good luck. I think it has saved us many
times. But it is high time we were able to REALLY do something more
than just pray.
> > It was supposed to make you think what would it be like if Tunguska
> > happened to hit Petersburg instead of trees.
>
> Even if that had happened, the damage would be considerably less than
> e.g. the damage caused by World Wars 1 and 2 ... and mankind survived
> these! Thus, Tunguska was never a threat to mankind -- man himself
> poses a greater threat to mankind than asteroid impact of similar
> magnitude as Tunguska.
WTC was nothing compared to WW1 and WW2 and yet people did consider it
a major loss.
> >>>>> As you have probably noticed after the 2002 EM7 flyby, we cannot
> >>>>> detect Tunguskas at such distances no matter whether the conditions
> >>>>> are favorable or not.
> >>>>
> >>>> If so, how come we know about 2002 EM7 ????? Here you seem to
> >>>> claim we cannot detect it, yet we know about it. How come?
> >>>
> >>> EM7 was detected by accident AFTER it passed its closest point but
> >>> then astronomers calculated where it was earlier.
> >>
> >> I know, but it WAS detected, and it will thus enter our statistics
> >> of NEA's.
> >
> > And statistics will say we can't detect such objects effectively.
>
> WHAT statistics?
>
> The efficiency factor here would me:
>
> no_of_detected_NEAs
> ------------------------------------------------
> no_of_detected_NEAs + no_of_undetected_NEAs
>
> Quite naturally, the quantity no_of_undetected_NEAs is unknown. So this
> is an example of guesswork, not statistics....
You said about putting EM7 into statistics not me.
> Also you said "statistics will say" --- do you think you can predict the
> future, or what?
No I am not another fancy kook infesting this group.
> >> However it wouldn't matter whether it had been detected a few days or
> >> so before closest approach, since that would have been too little
> >> time to chang eits path anyway. Path changes of Earth impacting
> >> asteroids must be performed years in advance.
> >
> > They must be performed years in advance because we have no means of
> > deflecting them effectively enough. And we don't because we haven't
> > tested using Clementine 2 what would actually happen after a real
> > projectile hits a real piece of damn rock but we just look at them and
> > guess.
>
> Sorry but I don't see how Clementine 2 could help in detecting these
> bodies... <g>
Sorry but I never claimed it would help in detecting them. I just
think some means of deflecting asteroids even when they are not
detected decades prior to impact would be really nice when we are
almost sure we cannot have warnings decades before impact because what
we do never has apprioperate funds and is therefore never reliable
enough.
> > It was not global although it did make slight changes to global
> > climate
>
> I don't think so. Yes it did eject a fair amount of dust in the
> atmosphere, perhaps as much as a major volcanic eruption. But I've
> never heard of any lasting climatic effect from Tunguska -- and since
> it happened soon 100 years ago, there's enough statistics to cover
> that if it did happen.
>
> > and such.
>
> What do you meah with "as such" here? Please be more specific.
The effects of the impact were observed in Europe. One could read a
newspaper after midnight because of the "fair amount of dust"
reflecting sunlight. I guess there could be some slight variations in
climate after even the small impacts but that is not the main point.
> > But we must realise what local really means in this
> > context: as far as I recall, the area was comparable to Germany.
> > Having Germany wiped out of the surface and international relations
> > would cause more havoc than wiping out two towers in NYC. It would be
> > a WTC event all over the country.
>
> The major thing about the WTC catastrophy was that it was caused by
> DELIBERATE ACTIONS BY PEOPLE. It was not a natural catastrophy, and
> that's why we now have a lot of increased safety measures here and
> there. If we count the number of dead only, that number in the WTC
> catastrophy wasn't larger than in e.g. the large earthquake in
> western Turkey a little more than 2 years earlier.
>
> "Having Germany wiped out" -- isn't that pretty much what happened
> during the end of WW II? Mankind, and even Germany, survived that...
> The "advantage" of a natural catastrophy here (as opposed to wars or
> terrorist actions) is that it won't have any political implications.
> Germany wasn't "only" almost wiped out during the end of WW II, it
> was also divided into two countries for almost 50 years afterwards.
"After WWII" was before globalisation was complete. Now Germany is
strongly involved in global relations as all major countries. If
Germany, Spain, France or UK were suddenly wiped out by a Tunguska, it
would have major implications for decades to follow.
> > It would be in a few hundred years and not millions as you imply.
>
> Now you're contradicting yourself! Earlier you correctly said this
> wasn't a prediction of an impact -- now you argue as if the impact
> was a fact rather than a mere 1 chance of 300.
>
> Now, if there's 1 chance of 300 of an asteroid impact every 1000 years
> or so, this means it'll be an actual impact every 300,000 years or
> so -- right?
Wrong, there probably will be NO impact in 2880 but this showed as a
general pattern that frequency of 1 in 300,000 years does not
necessairily mean it will happen IN 300,000 but might be MUCH earlier
- in a hundred years or next year - we just don't know. But we cannot
say that we do not have to worry because it won't happen until another
300,000 years pass.
> >>> And last time actually was 65 Gyrs ago.
> >>
> >> The Earth has existed for only some 5 Gyrs..... <evil grin>
> >
> > And global extinctions happened more than once.
>
> ... i.e. they weren't really extinctions since life survived.... <g>
> But you probably meant 65 Myrs rather than 65 Gyrs, didn't you?
> Be careful with those prefixes.....
Yeap, thanks. I meant Myrs. I sometimes get confused with these since
I am not a native English speaker. And if we call killing dinosaurs a
global extinction, there were some before the dinos and another one is
likely to happen.
> > There is no coverage in the southern hemisphere
>
> Doesn't matter much because no asteroid will remain in the far
> southern skies forever. Eventually they'll move up into the northern
> skies.
Does matter because we might miss a lot of potential future impactors
due to this. It is more a matter of favorable conditions.
> > and in the north the surveys miss 10 mag objects esily picked up by
> > amateurs.
>
> ALL such objects or only SOME of them? Also, if these objects are
> "easily" picked up by amateurs, as you here claim, then amateurs
> ought to be able to successfully run their own NEA program, right?
> And you could become one of them. So why don't you get an amateur
> telescope, then move to the southern hemisphere and save the world
> from destruction by discovering Earth-impacting NEA's which otherwise
> would remain undetected until impact? If you do this, you'll make it
> into the history books - wouldn't that be something?
I live in Poland and have not much prospects of moving south. Amateurs
are able to pick SOME of the objects that surveys have missed. I would
feel better if the surveys did not miss 10 mag comets.
> > And even if we detect dangerous NEOs we do not even know they are
> > dangerous because the calcualations lack precision as 1950DA story shows.
>
> The NEA program is only about a decade old -- in 1950 there was no
> such program. Today much fewer asteroids are lost, and a lot of
> previously lost asteroids are recovered. If the NEA program is run
> for another century or so, at some point the number of newly detected
> NEA's will probably decline sharply -- when this happens, it will be
> a clear indication that we've discovered almost all NEA's.
But the slow improvement of surveys may be disturbed by an actual
impact <evil grin>
> > We need an accurate model of asteroid behaviour. But we are not able
> > to produce it right now and therefore we should learn how to react on
> > scales better than decades. The impactor won't be so kind to let us
> > know a few decades in advance.
>
> 1950DA was kind enough to let us know about such a risk almost 900 years
> in advance.....
Only because we had excellent radar data and we usually don't.
> > What we really do right now is not far from ignoring.
>
> If so, why don't you get an amateur telescope, and then move to the
> southern hemisphere and save the world by discovering those asteroids
> everyone else ignores? Earlier you said amateurs could "easily" do
> this. Now, if you believe your own claims, what are you waiting for?
> Get going! Or do you really want to die? <grin>
No I don't and if I had enough cash I would move from Poland and do
exactly what you say. I would even set up my own NEAT, LONEOS or
LINEAR in the south if I could.
> > As it turned out during recent years the surveys are not accurate
> > at all and if there were no surveys it would not make much of a
> > difference.
>
> WHo made this conclusion, and where and when?
Me, in Poland, a few days ago - after 1950 DA news <grin> DA showed us
what getting the measurements SHOULD look like and the gov always
shows as they will NEVER be possible cause funding war is more
important than saving people.
> > We will have to improve them, the sooner the better, but in the mean
> > time we should test effective weapons since we are unprepared because
> > we do not even know WHEN to be prepared.
>
> WHat's the point of preparing yourself if you have no idea WHEN you
> need to be prepared?
If you told me I live in a dangerous neighbourhood and may be hurt any
moment I WOULD buy a gun although I would not know WHEN EXACTLY when
it will happen.
> >> BTW in today's paper I read that the asteroid 1950 DA has a 1-in-300
> >> risk of colliding with the Earth in -- 2880 !!!! Yep, that's in
> >> almost 900 years! We've got plenty of time to prepare for that
> >> one....
> >
> > I know, emotions make you wish there was only DA up there but another
> > news showed there might be TWICE as much asteroids than we thought.
> > And DA shows it is not a timescale of millions of years you hope for.
>
> 300 times 900 years is 270,000 years, i.e. about a quarter of a
> million years, so it's still a time scale of the order of magnitude
> of a million years. And even if there was TWICE as many asteroids as
> we thought, we most likely still have plenty of time.
Your calculations are right only if there were only objects like DA
and you know that.
> First we should survey as many NEA's as we can. When we've
> encountered a case with a known, or highly probable, Earth impact,
> THEN it's time to prepare counteractions. It took only 8 years to
> prepare for the manned moon landings (from the Kennedy speach to the
> actual first landing). Preparing a mission to deflect an asteroid is
> probably easire, since it won't have to be manned.
It would be much easier and much faster if we did some tests before we
Thad Floryan
| global catastrophy. Many more people are killed by e.g. floods or
| earthquakes than by meteor/asteroid impacts.
And people continue to rebuild homes and cities on flood plains (duh,
don't they understand WHY they're called flood plains?) and reside in
substandard domiciles in earthquake-prone regions.
This tells me [the majority of] people don't care and/or cannot see
beyond the present day.
| [...]
| That's nothing unique for asteroids! It's the same with floods,
| earthquakes, car crashes or diseases: we don't know beforehand
| WHEN or WHERE they will happen. That's why people don't perceive
| a car ride as a danger either.....
Flood plains will continue to flood, car crashes are preventable
(or would be with better driver training and vehicle maintenance
and the total elimination of drunk drivers), and disease epidemics
are due to ignorance or carelessness.
Earthquakes are caused by known forces about which we don't yet know
all the interactions, hence the lack of accurate prediction.
Perturbed asteroids, meteors or comets are another matter. Everyone
in this thread keeps harping about asteroids, yet two relatively recent
events (Tunguska, and the 500,000+ Carolina Bays) are most assuredly
cometary.
And how much warning would we have if a new comet pops out of the OORT
and heads towards Earth? 2 years?
| [...]
| Dinosaurs didn't monitor NEA's -- we do. Within only a hundred years
| or so (a very short time span from a cosmic perspective) we'll
| probably have learnt where most, if not all, NEA's large enough to
| pose a serious threat to us travel in their orbits, and so we'll be
| able to predict future impacts enough (i.e. a few decades or more) in
| advance to construct a deflection system when there really is such a
| threat.
Unless, say, a comet perturbs/deflects a known "safe" asteroid.
Again, stuff happens that we simply cannot predict [today].
| [...]
| And you ignore the statistics and assume an almost worst-case
| scenario for asteroid impacts but not so for other dangers to our
| lives. That's not a fair comparison...
Most risks and dangers to human life are understood and we deal with
them and get on with our lives. No big deal, happens all the time.
We don't have a catalog of all rogue bodies wandering through our Solar
System nor do we presently have any means to divert one should such pose
a threat. This is the point of reviving Clementine 2 and funding increased
radar and other mappings of the Solar System and beyond, especially the
breeding ground of comets.
Thad Floryan
| better than plain guesswork or arguments based on just emotions.
For non-life-threatening things like determining lottery winning odds,
sure. :-)
But chaos and randomness seems prevalent throughout the Universe, and
stuff happens (yeah, I know, I'm overusing that phrase). Since we're
still unable to recognize precursor events, we don't know with certainty
what will happen in the future. A "new" comet could be beyond Pluto at
the moment but heading to Earth and we'll have, what, only 2-3 years at
most warning?
| So it was perhaps as large as a not-too-large country. That's
| still "just" a regional catastrophy. If Tunguska had been a global
| catastrophy, all of Asia and Europe would have been seriously
| damaged -- but that didn't happen.
Consider the Carolina Bays I cited earlier. That was a relatively recent
event which left 500,000+ visible craters ranging from 200 feet to over
7 miles from New Jersey to Florida. The most-likely cause of both the
Tunguska and the Carolina Bays events was an aerial cometary explosion.
| > Ignoring asteroids is not a fair comparison.
|
| No-one says we shoudl ignore them. We should monitor them for now.
Again, that's one of the points of restarting Clementine 2 and funding radar
(and other) mapping of our Solar System.
Thad Floryan
| I wrote:
| The fact is that we don't know when the next impactor will hit. Analysis
| of lunar and Earth impact craters suggest something big (1 km or larger)
| hits Earth every 200,000 to 400,000 years. If you balance the potential loss
| of human life in such a catastrophic event, the odds of dying in an impact
| are about equal to those of dying in a plane crash. Now, planes crash every
| day. Big asteroids hit every 300,000 years or so.
Just curious: is anyone/anything monitoring the far side of the Moon nowadays?
Anything that would, today, impact the visible face of the Moon would more
likely than not be either shielded or deflected by Earth.
Bill Ferris
>Just curious: is anyone/anything monitoring the far side of the Moon
>nowadays?
The professional surveys can search where the Moon was within about 4 or 5
days. Similarly, they can survey where the Moon will be about the same amount
of time in advance. And since the Moon's orbital path keeps it in close
proximity to the ecliptic, those regions are thoroughly searched--weather
permitting--each lunation.
So, yes, the sky behind the Moon is being monitored.
Karol
So now when at least some of us basically agree the threat posed by
impactors either asteroids or comets is real and what we have now to
deal with this is far from enough, maybe we should start discussing
means of actually doing the things I proposed at the beginning of the
thread. What should we do to revive Clementine 2? What is the right
e-mail? Should we start signing a petition? What is the best way to
gain more funds for radar asteroid research? Should we organise
gathering donations? I will appreciate all sound suggestions on this
matter.
--
Karol
Martin Brown
Thad Floryan wrote:
> pau...@saaf.se (Paul Schlyter) wrote:
> | [...]
> | However, statistics isn't ALWAYS misleading! Statistics is usually
> | better than plain guesswork or arguments based on just emotions.
>
> For non-life-threatening things like determining lottery winning odds,
> sure. :-)
>
> But chaos and randomness seems prevalent throughout the Universe, and
> stuff happens (yeah, I know, I'm overusing that phrase).
And the statistical models provide a way to balance risk/cost/benefit and
support rational decisions about use of resources. Not much point in spending
the planets entire GNP on an asteroid defence system (which with our present
technology probably wouldn't work anyway) if in the meantime we all starve to
death or rebel against the usurious taxes needed to fund starwars II+.
How do you think insurance companies and pension funds balance their books ?
> Since we're still unable to recognize precursor events, we don't know with
> certainty
> what will happen in the future. A "new" comet could be beyond Pluto at
> the moment but heading to Earth and we'll have, what, only 2-3 years at most
> warning?
The odds against one coming in like that are very slender indeed. Think about
the target area the Earth offers in comparison with the area of a sphere radius
1AU centred on the sun.
ISTR the main worry is a scenario where a short period Earth crossing comet is
created by perturbations from one of the gas giants. In which case the odds get
a lot shorter. Even then I think the simulations show that Jupiter gets to
swallow a lot of them well before they do us any harm.
> | So it was perhaps as large as a not-too-large country. That's
> | still "just" a regional catastrophy. If Tunguska had been a global
> | catastrophy, all of Asia and Europe would have been seriously
> | damaged -- but that didn't happen.
>
> Consider the Carolina Bays I cited earlier. That was a relatively recent
> event which left 500,000+ visible craters ranging from 200 feet to over
> 7 miles from New Jersey to Florida. The most-likely cause of both the
> Tunguska and the Carolina Bays events was an aerial cometary explosion.
One thing we can say with a fair degree of certainty is that the probability
distribution of size of potential impactors follows an inverse power law
distribution - big ones are very very rare, dust is exceedingly common and
intermediate ones are pretty rare. It isn't worth worrying about very very low
probability events - you are far more likely to be struck by lightning from a
clear blue sky!
This is a fine example where the proposed "solution" (within our present
technical limitations) will be worse than the original problem it seeks to
address.
Regards,
Martin Brown
Karol
> > | However, statistics isn't ALWAYS misleading! Statistics is usually
> > | better than plain guesswork or arguments based on just emotions.
> >
> > For non-life-threatening things like determining lottery winning odds,
> > sure. :-)
> >
> > But chaos and randomness seems prevalent throughout the Universe, and
> > stuff happens (yeah, I know, I'm overusing that phrase).
>
> And the statistical models provide a way to balance risk/cost/benefit and
> support rational decisions about use of resources. Not much point in spending
> the planets entire GNP on an asteroid defence system (which with our present
> technology probably wouldn't work anyway) if in the meantime we all starve to
> death or rebel against the usurious taxes needed to fund starwars II+.
Oh, so there it goes all over again. I thought we've already cleared
this up. Look: noone is talking about spending "entire GNP" on an
asteroid defense system now. We just need some mere 100 M$ for
reviving Clementine 2 because we need to find out HOW to "make it
work" as you wish. Funds of this order of magnitude are easily waved
around within the national budget. And furthermore, we really do not
have to worry because it would be within the military's budget which
is enormous and they are going to spend a lot more anyway.
> How do you think insurance companies and pension funds balance their books ?
There may be no books because a Tunguska could wipe Washington DC and
not necessarily a Petersburg.
> > Since we're still unable to recognize precursor events, we don't know with
> > certainty
> > what will happen in the future. A "new" comet could be beyond Pluto at
> > the moment but heading to Earth and we'll have, what, only 2-3 years at most
> > warning?
>
> The odds against one coming in like that are very slender indeed. Think about
> the target area the Earth offers in comparison with the area of a sphere radius
> 1AU centred on the sun.
Yeah, another classical example of wishful thinking. Well, before
World War II, even in August 1939, most people said we do not need to
worry about another war and others claimed Hitler was really a nice
guy...
> ISTR the main worry is a scenario where a short period Earth crossing comet is
> created by perturbations from one of the gas giants. In which case the odds get
> a lot shorter. Even then I think the simulations show that Jupiter gets to
> swallow a lot of them well before they do us any harm.
Yeah, sure, everything in the Solar System was made in such a way to
protect the fragile little Earth. Sure Jupiter and Saturn did offer
some protection by wiping out most of them but they did not "swallow"
K-T Killer - Earth did.
> > | So it was perhaps as large as a not-too-large country. That's
> > | still "just" a regional catastrophy. If Tunguska had been a global
> > | catastrophy, all of Asia and Europe would have been seriously
> > | damaged -- but that didn't happen.
> >
> > Consider the Carolina Bays I cited earlier. That was a relatively recent
> > event which left 500,000+ visible craters ranging from 200 feet to over
> > 7 miles from New Jersey to Florida. The most-likely cause of both the
> > Tunguska and the Carolina Bays events was an aerial cometary explosion.
>
> One thing we can say with a fair degree of certainty is that the probability
> distribution of size of potential impactors follows an inverse power law
> distribution - big ones are very very rare, dust is exceedingly common and
> intermediate ones are pretty rare. It isn't worth worrying about very very low
> probability events - you are far more likely to be struck by lightning from a
> clear blue sky!
I am not aware of a lightning from a clear blue sky. I remember a car
struck by a meteor the size of a basketball and it did not look good.
But wait - there WAS a lightning from a clear sky. In 1993 when
something struck a rock in Poland called Babia Gora, the passage of
this object through the atmosphere caused sudden local presipitation
due to condensation of water vapor arounddust released on its way.
> This is a fine example where the proposed "solution" (within our present
> technical limitations) will be worse than the original problem it seeks to
> address.
I hope you will be as satisfied with your rhetorical tricks when there
will be a warning that will come too late and we won't have anything
in orbit because we decided not to care about asteroids in 2002.
--
Karol