Galileo Findings Boost Idea Of Other-Worldly Ocean On Europa
Ron Baalke
Headquarters, Washington, DC January 10, 2000
(Phone: 202/358-1753)
Jane Platt
Jet Propulsion Laboratory, Pasadena, CA
(Phone: 818/354-5011)
RELEASE: 00-7
GALILEO FINDINGS BOOST IDEA OF OTHER-WORLDLY OCEAN
When NASA's Galileo spacecraft swooped past Jupiter's moon
Europa a week ago, it picked up powerful new evidence that a liquid
ocean lies beneath Europa's icy crust.
As the spacecraft flew 218 miles (351 kilometers) above the
icy moon on January 3, its magnetometer instrument studied changes
in the direction of Europa's magnetic field. Galileo's
magnetometer observed directional changes consistent with the type
that would occur if Europa contained a shell of electrically
conducting material, such as a salty, liquid ocean.
"I think these findings tell us that there is indeed a layer
of liquid water beneath Europa's surface," said Dr. Margaret
Kivelson, principal investigator for the magnetometer. "I'm
cautious by nature, but this new evidence certainly makes the
argument for the presence of an ocean far more persuasive."
It appears that the ocean lies beneath the surface somewhere in
the outer 60 miles (about 100 kilometers), the approximate
thickness of the ice/water layer, according to Kivelson, a
researcher at the University of California, Los Angeles (UCLA).
"Jupiter's magnetic field at Europa's position changes
direction every 5-1/2 hours," Kivelson explained. "This changing
magnetic field can drive electrical currents in a conductor, such
as an ocean. Those currents produce a field similar to Earth's
magnetic field, but with its magnetic north pole -- the location
toward which a compass on Europa would point -- near Europa's
equator and constantly moving. In fact, it is actually reversing
direction entirely every 5-1/2 hours."
On previous Europa flybys, Galileo identified a magnetic north
pole, but did not determine whether its position changes with time.
"We wondered, 'Was it possible that the north pole did not move?' "
Kivelson said.
The new evidence was gathered during a flyby specially
planned so that the observed position of Europa's north pole would
make it clear whether or not it moves. In fact, Monday's data
showed that its position had moved, thus providing key evidence
for the existence of an ocean.
It is not likely that the electric currents on Europa flow
through solid surface ice, Kivelson explained, because ice is not a
good carrier of currents. "But melted ice containing salts, like
the sea water found on Earth, is a fairly good conductor," she
said.
There is no other likely current-carrying material near
Europa's surface, Kivelson added. "Currents could flow in
partially melted ice beneath Europa's surface, but that makes
little sense, since Europa is hotter toward its interior, so it's
more likely the ice would melt completely. In addition, as you get
deeper toward the interior, the strength of the current-generated
magnetic field at the surface would decrease."
These latest findings are consistent with previous Galileo
images and data showing a tortured surface seemingly formed when
Europa's surface ice broke and rearranged itself while floating on
a sea below. Further theoretical work is under way to analyze the
fluid layer and its properties.
"It will be interesting to see whether this same type of
phenomenon occurs at Jupiter's moon Ganymede," Kivelson said.
Galileo is tentatively scheduled to fly by Ganymede twice this
year.
Kivelson is joined in her magnetometer studies by Drs. Krishan
Khurana, Christopher Russell, Raymond Walker, Christophe Zimmer,
Martin Volwerk of UCLA, as well as Steven Joy and Joe Mafi, also of
UCLA, and Dr. Carole Polanskey of NASA's Jet Propulsion Laboratory
(JPL), Pasadena, CA.
Additional information and pictures taken by Galileo are
available at
The Galileo mission is managed for NASA's Office of Space
Science, Washington, D.C. by JPL, a division of the California
Institute of Technology, Pasadena, CA.
-end-
Jason Clayton
Ron Baalke <baa...@kelvin.jpl.nasa.gov> wrote in message
news:11JAN200...@kelvin.jpl.nasa.gov...
> Douglas Isbell
> Headquarters, Washington, DC January 10, 2000
> (Phone: 202/358-1753)
>
> Jane Platt
> Jet Propulsion Laboratory, Pasadena, CA
> (Phone: 818/354-5011)
>
> RELEASE: 00-7
>
> GALILEO FINDINGS BOOST IDEA OF OTHER-WORLDLY OCEAN
>
> the outer 60 miles (about 100 kilometers), the approximate
> thickness of the ice/water layer, according to Kivelson, a
> researcher at the University of California, Los Angeles (UCLA).
100 kilometers eh? So if we wanted to see this "ocean" we would have to
drill pretty deep. Does anyone have any info. on the approx. depth they
estimate is the shallowest? Also, how deep can we go on earth with drilling
technology? Taken into account that most drilling outfits I have seen are
way too big (I live in Houston, Texas and both grandfathers were oilfield
workers, so I know how big they can get) to launch on an Atlas or Titan,
hell even a Saturn V wouldn't work (maybe one of those big damn Russian
Energia's would do it, but in multiple parts). With that being said, how
the hell are we going to send something there to drill into the ice (let's
say it was only 100 meters to the nearest bit of ocean water), have it
perform tests and collect data, and then transmit the results back to earth?
I guess the 100 meters wouldn't be such a hard drill (if it is indeed that
close) and you could have a tether going back to the surface to send back
data to an orbiting craft. Sure sounds like a lot could go wrong with a
mission like that, you would probably want multiple drillers.
I know I am going to really hear from the anti-nuke crowd, but let's just
borrow some ideas from Edward Teller (Father of the U.S. H-bomb and advocate
of it's use as an earth-mover). What if we were to take a few of those
nasty little (about 10 megatons) h-bombs leftover from the cold war and
create a hole big enough to spew out some material into space that could
then be analyzed by an orbiting spacecraft? I know the idea sounds
ridiculous at first, but given our current track record for landing complex
missions that have too many things that can fail, and a dwindling NASA space
science budget, the idea starts to lend itself some creedance. Yes, if
there was a local ecosystem there (be a little far from the surface to use
photosynthesis as a food source, but who knows) it would very much disturb
it, but I don't suppose it could be any more populated than the Nevada
Desert, Siberia, or the South Pacific. If anyone has any other ideas on how
to go about exploring Europa (or know of any really good websites) I would
be interested in hearing them.
Jason Clayton
binomial
>100 kilometers eh? So if we wanted to see this "ocean" we would have to
>drill pretty deep.
Much like we know the Earth has fluid in the center from observing waves
generated from earthquakes (I think that's where they're from!), couldn't we
do the same idea on Europa? Somehow make those waves on one side of the
moon, and then have equipment record what happens on the other?...So we know
something is there before we dig. :)
rk
I believe you are correct. If we soft-land some seismometers [too early in the
morning, check the spelling yourself!] on different parts of the moon and then
create a large force, we should get some idea of what's in it, by transmissions
of the waves. For stimulus(*) we can hard-land the Mars 2001 lander, gutted for
just this impact mission.
(*) Note, this is sarcastic humor. This notice appears for those who are truly
humor-impaired.
----------------------------------------------------------------------
rk The world of space holds vast promise
stellar engineering, ltd. for the service of man, and it is a
stel...@erols.com.NOSPAM world we have only begun to explore.
Hi-Rel Digital Systems Design -- James E. Webb, 1968
Matthew Montchalin
On Tue, 11 Jan 2000, binomial wrote:
|>100 kilometers eh? So if we wanted to see this "ocean" we would have to
|>drill pretty deep.
|
|Much like we know the Earth has fluid in the center from observing waves
|generated from earthquakes (I think that's where they're from!), couldn't we
|do the same idea on Europa? Somehow make those waves on one side of the
|moon, and then have equipment record what happens on the other?...So we know
|something is there before we dig. :)
If you want to be sequential, you do the following:
1) Get a satellite in 'permanent' orbit around Europa. Do a deep-radar
scanning of the whole darn thing.
2) Try to land a seismometer-bot there, and in case something goes
wrong, let's make that FOUR seismometer-bots.
3) Now look for 'moon-quakes' and see where the faults are. If we
are real lucky, we can excavate some 'faults' and look for the
remains of life forms that happen to have been sprayed into the
cracks every time there is a cataclysmic shake up.
4) So, if we made it this far, we may not have to get under the crust.
The remains of 'life' may already be frozen, and readily available
without having to dig too deep. :)
Chris
this would require a power source probably the size of your drilling rig.
So then I thought "big magnifying glass". If you could make a large but
collapsible magnifying glass out of composite plastics and put it into a
stationary orbit (This is the tricky part I think) between the sun and
Europa you could let the sun drill the hole for you.
The giant lens could be created similar to a breast implant shaped like a
lens rather than a boob. A huge plastic bag filled with water harvested from
the moon.
"Jason Clayton" <jaso...@comwerx.net> wrote in message
news:mtUe4.820$9T4....@nnrp2.rcsntx.swbell.net...
>
> Ron Baalke <baa...@kelvin.jpl.nasa.gov> wrote in message
> news:11JAN200...@kelvin.jpl.nasa.gov...
> > Douglas Isbell
> > Headquarters, Washington, DC January 10, 2000
> > (Phone: 202/358-1753)
> >
> > Jane Platt
> > Jet Propulsion Laboratory, Pasadena, CA
> > (Phone: 818/354-5011)
> >
> > RELEASE: 00-7
> >
> > GALILEO FINDINGS BOOST IDEA OF OTHER-WORLDLY OCEAN
> >
> > It appears that the ocean lies beneath the surface somewhere in
> > the outer 60 miles (about 100 kilometers), the approximate
> > thickness of the ice/water layer, according to Kivelson, a
> > researcher at the University of California, Los Angeles (UCLA).
>
> 100 kilometers eh? So if we wanted to see this "ocean" we would have to
Russell Martin
you keep the same spot on Europa on the optical axis formed by
the sun and the lens when the whole system is orbiting around?
Chris wrote:
>
> At first I thought "laser"! Just use a laser to drill through the ice. But
> this would require a power source probably the size of your drilling rig.
> So then I thought "big magnifying glass". If you could make a large but
> collapsible magnifying glass out of composite plastics and put it into a
> stationary orbit (This is the tricky part I think) between the sun and
> Europa you could let the sun drill the hole for you.
> The giant lens could be created similar to a breast implant shaped like a
> lens rather than a boob. A huge plastic bag filled with water harvested from
> the moon.
snipped
Russell Martin
>
> binomial wrote:
>
> > >100 kilometers eh? So if we wanted to see this "ocean" we would have to
> > >drill pretty deep.
> >
> > generated from earthquakes (I think that's where they're from!), couldn't we
> > do the same idea on Europa? Somehow make those waves on one side of the
> > moon, and then have equipment record what happens on the other?...So we know
> > something is there before we dig. :)
>
> morning, check the spelling yourself!] on different parts of the moon and then
> create a large force, we should get some idea of what's in it, by transmissions
> of the waves. For stimulus(*) we can hard-land the Mars 2001 lander, gutted for
> just this impact mission.
>
We might not even have to order NASA to try to hit Europa with it.
At the rate things are going it might hit Europa even if aimed at
Mars.**
> (*) Note, this is sarcastic humor. This notice appears for those who are truly
> humor-impaired.
** Ditto.
David Boll
: At first I thought "laser"! Just use a laser to drill through the ice. But
: this would require a power source probably the size of your drilling rig.
: So then I thought "big magnifying glass".
I think melting your way through the ice would be the easiest. An RTG-powered
and heated probe could melt its way through eventually. Plus, we could
even test the theory on Earth first...
--
Dave Boll
http://www.frii.com/~dboll/
katzenhai
be IF weÿffffb4re supposed to do it.
Iÿffffb4m no scientist and really not too familiar with the topic.
So pardon me for my unprofessional contribution. But as far
as Iÿffffb4m informed, the possibility of the existence of fluid
water beneath that layer of ice also makes it possible that
there COULD be "primitive" life as well.
After human beings got so far to understand the complexity
behind the chemical and biological evolution, after we know
that external influences can change or spoil the development
of life - how on earth can we take the risk to probably
disturb whatÿffffb4s maybe going on on Europa?
Donÿffffb4t get me wrong, there is no theological intention behind
this, not at all. But just because Science made us able to
understand what the possibility of the evolution of life
means, it should also have tought us that itÿffffb4s our duty not
to influence this possibility - even if that means that we
once have to to put back our legitimate yearning for
knowledge. In interest of and out of respect for what
probably happens on Europa. Because we KNOW.
* Sent from AltaVista http://www.altavista.com Where you can also find related Web Pages, Images, Audios, Videos, News, and Shopping. Smart is Beautiful
Mike Williams
>At first I thought "laser"! Just use a laser to drill through the ice. But
>this would require a power source probably the size of your drilling rig.
>collapsible magnifying glass out of composite plastics and put it into a
>stationary orbit (This is the tricky part I think) between the sun and
>Europa you could let the sun drill the hole for you.
>The giant lens could be created similar to a breast implant shaped like a
>lens rather than a boob. A huge plastic bag filled with water harvested from
>the moon.
The problem with any solution like that is that you have to find a way
to get the heat down through 60 miles of ice. Ice and water aren't
sufficiently transparent for lasers or concentrated sunlight to work
(see how dark it is at the bottom of our own oceans, and that's only a
few miles of water).
A much easier way is to take a nuclear power pack, like what they use
for most deep space missions but perhaps a bit beefier, and just use it
to keep the drilling bit warm enough to melt a little bit of ice
immediately around it. So at any instant, there's only a small melted
pocket surrounding the bit. On the top side of the bit there'd be a 60
mile coil of wire which unravels as the bit descends. The ice refreezes
around the uncoiled wire as the bit descends. The wire carries commands
and data to and from a surface module which relays the data back to
Earth.
--
Mike Williams + #
Gentleman of Leisure
Jan Panteltje
>be IF weÿffffb4re supposed to do it.
>Iÿffffb4m no scientist and really not too familiar with the topic.
>So pardon me for my unprofessional contribution. But as far
>as Iÿffffb4m informed, the possibility of the existence of fluid
>water beneath that layer of ice also makes it possible that
>there COULD be "primitive" life as well.
>
>After human beings got so far to understand the complexity
>behind the chemical and biological evolution, after we know
>that external influences can change or spoil the development
>of life - how on earth can we take the risk to probably
>disturb whatÿffffb4s maybe going on on Europa?
>
>Donÿffffb4t get me wrong, there is no theological intention behind
Jan Panteltje
Jan
Matthew Montchalin
|>disturb whatÿffffb4s maybe going on on Europa?
|>
|>Donÿffffb4t get me wrong, there is no theological intention behind
|What is all this whatÿffffb4???
He must be using a proprietary ASCII scheme. For instance, 1b, ff, ff,
b4. He is using 32 bits instead of the universally recommended 7 bits
that the rest of us use.
Matthew Montchalin
|>After human beings got so far to understand the complexity
|>behind the chemical and biological evolution, after we know
|>that external influences can change or spoil the development
|>of life - how on earth can we take the risk to probably
Don't worry about it.
The most practical and convenient way of checking for life products on
Europa is by bulldozing some of the ice from the crust --- that is where
the 'tectonic' processes in Europa tend to deposit the 'microbial'
remains of life there. If there is life inside of Europa, there will be
signs of life in the ice that gets deposited on the crust there.
It shouldn't take too much work to reconstitute the life forms right
there on the crust without having to disturb the ocean underneath.
If we were *really* lucky, there might even be fossilized remains of
multi-cellular life in the ice as well. Might make for a very
interesting long-term exploration there, and all of this without
having to dig deep into Europa. Environmentalists and "environmental"
separatists would not have to worry about us disturbing the vast oceans
under the crust --- we would concentrate our efforts analyzing the
fossilized remains that are readily available in the crust.
DaveKa
through the ice down to the liquid ocean.
Dave
Jason Clayton <jaso...@comwerx.net> wrote in message
news:mtUe4.820$9T4....@nnrp2.rcsntx.swbell.net...
>
> Ron Baalke <baa...@kelvin.jpl.nasa.gov> wrote in message
> news:11JAN200...@kelvin.jpl.nasa.gov...
> > Douglas Isbell
> > Headquarters, Washington, DC January 10, 2000
> > (Phone: 202/358-1753)
> >
> > Jane Platt
> > Jet Propulsion Laboratory, Pasadena, CA
> > (Phone: 818/354-5011)
> >
> > RELEASE: 00-7
> >
> > GALILEO FINDINGS BOOST IDEA OF OTHER-WORLDLY OCEAN
> >
> > It appears that the ocean lies beneath the surface somewhere in
> > the outer 60 miles (about 100 kilometers), the approximate
> > thickness of the ice/water layer, according to Kivelson, a
> > researcher at the University of California, Los Angeles (UCLA).
>
> 100 kilometers eh? So if we wanted to see this "ocean" we would have to
Matthew Montchalin
|You wouldn't need to drill. Just a probe that would heat up and melt
|through the ice down to the liquid ocean.
You don't even have to do that.
If there is life in the ocean below, natural depositional processes
will throw out *plenty* of life remnants into the surface crust, so
even a simple bulldozer will be enough to dig out a good number of
'fossils' to analyze.
Matthew Montchalin
On Thu, 13 Jan 2000, Christof Kuhn wrote:
|What would it mean if there was liquid water on Europa? There is plenty
|of water in the universe, but life is not made of water.
By examining the 'fossilized' microbial matter frozen into the crust of
Europa, a lot could be learned. No, I don't think we will be finding
'shaggy mammoths' in the ice, but it would not be so far-fetched to find
microbial algaes and plankton encased in the ice of the crust.
|What's more important is carbohydrates or amino acids. Has there any
|evidence been found outside the earth?
|
|I really fear that there are a lot of companies who are anxious about
|their future field of work and consequently, they try to make the public
|believe it's really crucial for human existence to know about the
|interior of extraterrestrial bodies.
There is no need to examine the interior of Europa when there is so
much to be learned about the crust of Europa. But if there are signs
of multi-celled microbial life in Europa, there will be a lot to make
of it. It would be interesting to see if anyone can reconstitute the
microbial remains to be found in the crust of Europa. In fact, that
might even make for a great science fiction story. :)
Christof Kuhn
>
> When NASA's Galileo spacecraft swooped past Jupiter's moon
> Europa a week ago, it picked up powerful new evidence that a liquid
> ocean lies beneath Europa's icy crust.
>
In my opinion, there is far too much excitement about "life on other
planets". I guess it's just a good argument for scientists to persuade
the public that it's really important what they're doing.
What would it mean if there was liquid water on Europa? There is plenty
of water in the universe, but life is not made of water.
What's more important is carbohydrates or amino acids. Has there any
evidence been found outside the earth?
I really fear that there are a lot of companies who are anxious about
their future field of work and consequently, they try to make the public
believe it's really crucial for human existence to know about the
interior of extraterrestrial bodies.
Don't get me wrong - I really think that basic sciences are important
for inventions nobody dreams of so far. But as regards missions to other
planets, I think that this money should be spent on other topics.
Cheers, Christof
---
Christof Kuhn
Inst. f. Angewandte Geologie,
Univ. f. BoKu Wien, Austria
h944...@edv1.boku.ac.at
http://homepage.boku.ac.at/h9440283/index.htm
lad...@my-deja.com
h944...@edv1.boku.ac.at wrote:
> Ron Baalke wrote:
> >
> > When NASA's Galileo spacecraft swooped past Jupiter's moon
> > Europa a week ago, it picked up powerful new evidence that a liquid
> > ocean lies beneath Europa's icy crust.
> >
>
> In my opinion, there is far too much excitement about "life on other
> planets". I guess it's just a good argument for scientists to persuade
> the public that it's really important what they're doing.
I'm a scientist, and I'm excited. You're not?
> What would it mean if there was liquid water on Europa? There is plenty
> of water in the universe, but life is not made of water.
>
> What's more important is carbohydrates or amino acids. Has there any
> evidence been found outside the earth?
Amino acids, definitely. See, for example, the studies of the Murchison
meteorite. I also recall that a recent spectroscopic study of the
molecules in interstellar dust identified glycine, but I can't locate the
reference at the moment.
> ---
> Christof Kuhn
> Inst. f. Angewandte Geologie,
> Univ. f. BoKu Wien, Austria
--
John J. Ladasky Jr., Ph.D.
Department of Structural Biology
Stanford University Medical Center
Stanford, CA 94305
Secretary, Californians for Renewable Energy <http://www.calfree.com>
Sent via Deja.com http://www.deja.com/
Before you buy.
lad...@my-deja.com
"Jason Clayton" <jaso...@comwerx.net> wrote:
> Ron Baalke <baa...@kelvin.jpl.nasa.gov> wrote in message
> news:11JAN200...@kelvin.jpl.nasa.gov...
> > Douglas Isbell
> > Headquarters, Washington, DC January 10, 2000
> > (Phone: 202/358-1753)
> >
> > Jane Platt
> > Jet Propulsion Laboratory, Pasadena, CA
> > (Phone: 818/354-5011)
> >
> > RELEASE: 00-7
> >
> > GALILEO FINDINGS BOOST IDEA OF OTHER-WORLDLY OCEAN
> >
> > It appears that the ocean lies beneath the surface somewhere in
> > the outer 60 miles (about 100 kilometers), the approximate
> > thickness of the ice/water layer, according to Kivelson, a
> > researcher at the University of California, Los Angeles (UCLA).
[snip]
> I know I am going to really hear from the anti-nuke crowd, but let's
> just borrow some ideas from Edward Teller (Father of the U.S. H-bomb
> and advocate of it's use as an earth-mover). What if we were to take
> a few of those nasty little (about 10 megatons) h-bombs leftover from
> the cold war and create a hole big enough to spew out some material
> into space that could then be analyzed by an orbiting spacecraft? I
> know the idea sounds ridiculous at first,
Well, this is a *bit* more drastic than the crashing of the Lunar
Prospector into the Moon, wouldn't you say?
Nuke or no nuke, I think that the idea of liberating interesting material
from the Europan subsurface with a bomb would probably not work. Impact
craters tend to be very shallow. An explosion-induced crater probably
wouldn't be much deeper. Think of the Winslow Meteor Crater in Arizona:
the impact energy is estimated to be the equivalent of a 20-40 megaton
explosion, yet it's only 175 meters deep. What would it take to reach an
ocean even 1 kilometer deep? (Taking a wild guess that the crater depth
scales with the cube root of the explosion energy, you would need about
5,000 megatons!)
There are several other problems with this scheme. How would you analyze
the ejecta? I don't think that a spectroscopic analysis will tell you
whether there is any life in the Europan ocean... you may find evidence
of amino acids and carbohydrates, but they wouldn't conclusively indicate
life. Such compounds are also found in carbonaceous meteorites.
Would you attempt to physically retrieve some of the debris, say with an
aerogel as is being done with the Stardust probe? How much material can
you realistically expect to harvest? What might the explosion have done
to the material? And how would you analyze it? Stardust is bringing its
samples back to Earth -- a VERY expensive proposition, from Jupiter's
gravity well.
[snip]
> Yes, if there was a local ecosystem there (be a little far from the
> surface to use photosynthesis as a food source, but who knows) it
> would very much disturb it, but I don't suppose it could be any more
> populated than the Nevada Desert, Siberia, or the South Pacific.
It doesn't matter how populated that ecosystem might be. The disturbance
would be incredibly catastrophic. And the lack of photosynthesis places
no limit on the density of life. Take a look at the amazing density and
diversity of the ecosystems surrounding deep-sea vents. The organisms at
the bottom of the food chain in these systems are chemotrophs -- they
obtain their energy entirely without sunlight.
> If anyone has any other ideas on how to go about exploring Europa
>(or know of any really good websites) I would
> be interested in hearing them.
Several other people have already posted the concept of using a
radioisotope thermal generator (RTG) to melt through the ice. I seem to
recall that this idea originated at JPL, but at the moment I can't locate
any references to it. Anyone?
I'm a biologist. I'd like to see the Europa Sea Explorer, if it ever
gets built, equipped with a microscope.
Richard Hendricks
Those devious NASA engineers!
Skywise
<Snipola>
> What's more important is carbohydrates or amino acids. Has there any
> evidence been found outside the earth?
Yes. Do a search for "interstellar carbohydrates" or "interstellar amino
acids" on a search engine.
One link I found is http://monet.astro.uiuc.edu/~dmehring/dmehring.html
where the author lists many of the molecules he's observed via radio
astronomy, some of them being carbohydrates.
Also on that site is a link to someone doing interstellar amino acid
research.
I seem to recall some amino acids being found somewhere, I think in an
interstellar cloud.
--
S*k*y*w*i*s*e
http://home.earthlink.net/~skywise711/ Laser & Optics links galore!!!
SEN...@argo.rhein-neckar.de
>You wouldn't need to drill. Just a probe that would heat up and melt
>through the ice down to the liquid ocean.
>
Such a type of Europa probe was discussed here in alt/sci/planetary
or sci/space/tech about a year ago up to some detail. In the later
even 5 years ago before Dejanews!
>Absender : hig...@fnalv.fnal.gov (Bill Higgins-- Beam Jockey)
>Betreff : Melt-Mobile (was Re: Probing Europa's Oceans (was Re: Europa...))
>Datum : Do 16.03.95, 13:30 (erhalten: 19.03.95)
>----------------------------------------------------------------------
>In article <lpurpleD...@netcom.com>, lpu...@netcom.com (Lance Purple) writes:
>> Brian Yamauchi <yama...@ces.cwru.edu> asks:
>>>
>>>Suppose you landed a nuclear reactor (a Topaz, for example) on
>>>Europa's surface . . . then triggered a meltdown.
>
>[Lance's clever RTG-based design ideas omitted]
>
>Nobody has pointed out that in the early Sixties, somebody proposed
>building a probe like this for exploring the Earth's crust. Build a
>tall torpedo-shaped vehicle out of materials which can resist extremely
>high temperatures (I don't know, over 1000 K? 2000 K?) Start up the
>nuclear reactor within it and it will begin to melt the rock it's
>parked on. It descends to a predetermined depth, or maybe waits for a
>predetermined time, somehow trapping magma samples along the way.
>Then it drops its lower end, which is dense ballast, and melts its way
>back up to the surface.
>
>The ultimate "not in MY back yard!" toy.
>
>No references handy, but it was mentioned in the "Science" section of
>*Time* when I was in grade school, so it's possible to track down.
>
>A tamer version might make a good basis for an icy-satellite probe,
>especially since it would be at least half a billion miles away from
>my back yard.
>
>1. Push Button | Bill Higgins
>2. Rub Hands Briskly Under Warm Air | Fermilab
>3. Stops Automatically | Internet: hig...@fnal.fnal.gov
>4. Wipe Hands On Pants | Bitnet: higgins@fnal
>
It has similarities to this proposed "Earth Diver" by Edward Teller.
Propeing deeps unreachable for drills. (But generating a steam explosion
if contacting water rich layers?)
The feasibility of a Europa Diver seems out of question. But first
we need a Europa Orbiter with a low frequency sounding radar and
stereo mapper camera to select a landing site. Somewhere on
a NASA site I saw a first proposal for such a Orbiter. Hope they
get a tuneable color laser or a hyperspectral camera on bord.
Could be a way to detect fosile life deposites in the ice. Or
it could detect gas clouds venting from break zones. As more
pro live data the orbiter gets as more money for divers is sure.
We habe reason to expect fish like animals below the ice.
Evolution had a lot of time and a very stable environment.
No meteorites like on earths past. Or atmospheric vulcano
clouds interrupting the sun radiation. Only stable heating
by Jupiters tidal forces. Underwater vulcanos in high
pressure environment seem not to be so much devastating in
eruption. Would be funny if we detect live on Europe before
Mars.
cheers
SENECA
## CrossPoint v3.1 ##
Bruce D. Winningham
<bino...@random.variable> wrote:
>Much like we know the Earth has fluid in the center from observing waves
>generated from earthquakes (I think that's where they're from!),
I am sorry but the wave thing is not good enough scientific and
conclusive evidence for me in judging what the center of the earth is
made of. Anyone agree or disagree?
Bruce Winningham
Damien Douxchamps
>
> On Wed, 12 Jan 2000, Jan Panteltje wrote:
> |>disturb whatÿffffb4s maybe going on on Europa?
> |>
> |What is all this whatÿffffb4???
>
> He must be using a proprietary ASCII scheme. For instance, 1b, ff, ff,
> b4. He is using 32 bits instead of the universally recommended 7 bits
> that the rest of us use.
>
from Europa? :-)
Damien
--
Damien Douxchamps
URL : http://www.tele.ucl.ac.be/MEMBERS/Douxchamps_Damien_e.html
Jan Panteltje
Do you think life spontanously occurs in a closed vessel,
without exposure to radiation or radiative energy from the sun?
I really do not know what is needed as a trigger :)
But indeed fish or at least microbes could swim there.
And what about polar bears? mmm, maybe these just migrated north on earth..
Hey what about eskimos? living in iglos? we need a better camera ..
Fun is it not, I would volunteer for a mission, but probably to cold there.
Jan
Jan Panteltje
>
>> If anyone has any other ideas on how to go about exploring Europa
>>(or know of any really good websites) I would
>> be interested in hearing them.
>
>Several other people have already posted the concept of using a
>radioisotope thermal generator (RTG) to melt through the ice. I seem to
>recall that this idea originated at JPL, but at the moment I can't locate
>any references to it. Anyone?
>
>I'm a biologist. I'd like to see the Europa Sea Explorer, if it ever
>gets built, equipped with a microscope.
>
>--
>John J. Ladasky Jr., Ph.D.
>Department of Structural Biology
>Stanford University Medical Center
>Stanford, CA 94305
>Secretary, Californians for Renewable Energy <http://www.calfree.com>
>
>
>Sent via Deja.com http://www.deja.com/
>Before you buy.
>
handed' molucules (or was it left handed ;)) or something, that was done by
the same persons that designed the experiment on the first mars probe, that
was POSITIVE, would give an indication of life?
The following URL may be also of interest to you:
www.spie.org/web/abstracts/3100/3111.htm
Jan
Martyn Harrison
<Dave_...@email.msn.com> wrote:
>You wouldn't need to drill. Just a probe that would heat up and melt
>through the ice down to the liquid ocean.
Hmm, let's put some figures around that. I'll imagine that the ice is
pretty cold, sub zero to begin with and warming up to melting point
underneath. The device will need to be, what, about quarter of a
square meter in area? So it has to melt about 25,000 cubic meters of
ice, or 25,000,000,000 ccs.
It also has to "sink" about 100,000 meters.
Whatever provides the heat will have to put out, say, 100 degrees K of
heat to begin with, although as it nears the bottom it will probably
only need a degree or so to melt the ice near the liquid layer.
So if the heater produces, say, a kilowatt of heat initially, it could
melt by 1 degree about 250 ccs per second, roughly, so for the first
centimeter it will take 100 seconds. Letting the heat output decrease
as it sinks gradually through the ice as its fuel grows less energetic
(this is an RTG?) means that we probably see this sort of speed all
the way down. I get a figure of 100,000 m* 100 cm * 100 kelvin in
seconds, or about 10^9 seconds. Overall, 10^12 joules of energy for
the whole thing, too. Starts to sound like an atomic bomb.
And it would take hundreds of years. Refinements welcome, this is back
of the envelope stuff open to correction.
John Rehling
(among other things) an altimeter that produces a topographic map of
Europa so accurate that the tidal distortions are measured. Then, it
will be easy to see from the size of the tides if it is ice that is
being distorted, or water with a layer of ice on top.
There are impact craters 30km across on Europa that do not break
through to ocean, so it seems unlikley that we could nuke our way
through very easily.
Something that melts down to the ocean is a nice idea, though if the
crust is not pure ice, it may not be so easy.
-JAR
--
It wouldn't have been failure to be bankrupt, dishonored, pilloried,
hanged; it was failure not to be anything.
-Henry James, "The Beast in the Jungle"
Dale Firmin
binomial wrote:
> Much like we know the Earth has fluid in the center from observing waves
> generated from earthquakes (I think that's where they're from!), couldn't we
> do the same idea on Europa? Somehow make those waves on one side of the
> moon, and then have equipment record what happens on the other?...So we know
> something is there before we dig. :)
Don't have too. A recent article in one of the astronomy magazines (I forget
which one and don't feel like digging it up) says that one can simply measure
the size of the tide. The solid ice crust gives a lot as shown by all the
cracks. A liquid ocean underneath should move a great deal at high tide even
against the resistance of a thick ice crust. If it's solid ice, it would move
very little. Therefore we only need to orbit a satellite with a radar capable
of accurately measuring its altitude and then just measure the tide.
Dale
Zirb-Monkey
> At first I thought "laser"! Just use a laser to drill through the ice. But
> this would require a power source probably the size of your drilling rig.
> So then I thought "big magnifying glass". If you could make a large but
> collapsible magnifying glass out of composite plastics and put it into a
> stationary orbit (This is the tricky part I think) between the sun and
> Europa you could let the sun drill the hole for you.
> The giant lens could be created similar to a breast implant shaped like a
> lens rather than a boob. A huge plastic bag filled with water harvested from
> the moon.
I'd think it would be cool to have a huge orbiting boob shining a beam of light
on Europa. But then what size implant would we use? A DDDDDDDDDDDDDD cup, of
would we just call it a Z cup. But if we make one for Europa, then porno stars
will want to have these also. This will make the plan more cost effective
because the research needed to make one would be covered by the purchases of
others not for use in outer space. The more produced, the less research cost
per unit. I think your orbiting boob plan is great. But if we send one, we'd
have to send another to balance out the ice moon, after all, we don't want to
make it look lop-sided.
Bill Higgins-- Beam Jockey
> Such a type of Europa probe was discussed here in alt/sci/planetary
> or sci/space/tech about a year ago up to some detail. In the later
> even 5 years ago before Dejanews!
Wow, I didn't expect my five-year-old postings to be quoted here!
>>Absender : hig...@fnalv.fnal.gov (Bill Higgins-- Beam Jockey)
>>Betreff : Melt-Mobile (was Re: Probing Europa's Oceans (was Re: Europa...))
>>Datum : Do 16.03.95, 13:30 (erhalten: 19.03.95)
>>----------------------------------------------------------------------
>>In article <lpurpleD...@netcom.com>, lpu...@netcom.com (Lance Purple) *
>>> Brian Yamauchi <yama...@ces.cwru.edu> asks:
>>>>
>>>>Suppose you landed a nuclear reactor (a Topaz, for example) on
>>>>Europa's surface . . . then triggered a meltdown.
>>
>>[Lance's clever RTG-based design ideas omitted]
>>
>>Nobody has pointed out that in the early Sixties, somebody proposed
>>building a probe like this for exploring the Earth's crust. Build a
>>tall torpedo-shaped vehicle out of materials which can resist extremely
>>high temperatures (I don't know, over 1000 K? 2000 K?) Start up the
>>nuclear reactor within it and it will begin to melt the rock it's
>>parked on. It descends to a predetermined depth, or maybe waits for a
>>predetermined time, somehow trapping magma samples along the way.
>>Then it drops its lower end, which is dense ballast, and melts its way
>>back up to the surface.
>>
>>The ultimate "not in MY back yard!" toy.
>>
>>No references handy, but it was mentioned in the "Science" section of
>>*Time* when I was in grade school, so it's possible to track down.
I have since done some research on this. William Manchester Adams, a
geophysicist at Lawrence Livermore National Laboratory, in 1961 patented a
gadget like this. I don't know where he is now, but he was working at
Western Washington Univeristy in 1990.
> It has similarities to this proposed "Earth Diver" by Edward Teller.
Teller ran Livermore around that time; perhaps he knew Adams and his scheme?
--
___ O~~* /_) ' / / /_/ ' , , ' ,_ _ \|/
/ / - ~ -~~~~~~~~/_) / / / / / / (_) (_) / / / _\~~~~~~~~~~~zap!
/__// \ (_) (_) / | \
| | Bill Higgins Fermi National Accelerator Laboratory
\ / Bitnet: Sic transit gloria mundi
- - Internet: HIG...@FNAL.FNAL.GOV
~ SPAN/Hepnet/Physnet: 43011::HIGGINS
Bill Higgins-- Beam Jockey
> The current Europa Orbiter plan to find evidence of an ocean keys on
> (among other things) an altimeter that produces a topographic map of
> Europa so accurate that the tidal distortions are measured. Then, it
> will be easy to see from the size of the tides if it is ice that is
> being distorted, or water with a layer of ice on top.
This sounds hard to me, but I would like to see technical details.
A committee of scientists has just published a new report planning the
exploration of Europa. See
<http://www.nationalacademies.org/ssb/comp-europamenu.htm>. The summary
suggests that they want to measure the changes in topography with a
resolution of about 2 meters.
> There are impact craters 30km across on Europa that do not break
> through to ocean, so it seems unlikley that we could nuke our way
> through very easily.
>
> Something that melts down to the ocean is a nice idea, though if the
> crust is not pure ice, it may not be so easy.
The crust is probably fairly pure, or it wouldn't have such a high albedo. I
don't think there are a lot of silicates mixed in with it, if that's what
you're thinking.
--
As my advisor said: "The tragedy of Galois | Bill Higgins
is that he could have contributed | Fermilab
so much more to mathematics if he'd only | Internet: hig...@fnal.fnal.gov
spent more time on his marksmanship." | Bitnet: Sic transit gloria mundi
--Olin Shivers
Bill Higgins-- Beam Jockey
>
> If you want to be sequential, you do the following:
>
> 1) Get a satellite in 'permanent' orbit around Europa. Do a deep-radar
> scanning of the whole darn thing.
>
> 2) Try to land a seismometer-bot there, and in case something goes
> wrong, let's make that FOUR seismometer-bots.
>
> 3) Now look for 'moon-quakes' and see where the faults are. If we
> are real lucky, we can excavate some 'faults' and look for the
> remains of life forms that happen to have been sprayed into the
> cracks every time there is a cataclysmic shake up.
Um, look at a picture of Europa. It's covered with linear "cracks" called
linea. You don't need a seismometer-bot to see where the faults are.
Research has established that the linear features mostly align with the
places where you'd expect tidal flexing to create the most stress.
> 4) So, if we made it this far, we may not have to get under the crust.
> The remains of 'life' may already be frozen, and readily available
> without having to dig too deep. :)
This is a pretty good idea. Land near the freshest-looking cracks, or other
freshly-disrupted surface, and use a rover to collect samples of material.
One can probably get some idea of the geochemistry of the interior this way,
though establishing the spatial and temporal origin of your samples may be
difficult.
The overlapping linea, looking in some places like a photo of a bowl of
spaghetti, probably lend themselves to constructing stratigraphic sequences,
at least on a local scale. So patient photogeologists may be able to
construct a partial "story" for Europa's surface long before any spacecraft
lands there. They can recommend the best places to look.
--
Bill Higgins, Beam Jockey | "Treat your password like
Fermi National Accelerator Laboratory | your toothbrush. Don't let
Bitnet: Sic transit gloria mundi | anybody else use it--
Internet: HIG...@FNAL.FNAL.GOV | and get a new one every
SPAN/Hepnet: 43009::HIGGINS | six months." --Cliff Stoll
Bill Higgins-- Beam Jockey
> Would you attempt to physically retrieve some of the debris, say with an
> aerogel as is being done with the Stardust probe? How much material can
> you realistically expect to harvest? What might the explosion have done
> to the material? And how would you analyze it? Stardust is bringing its
> samples back to Earth -- a VERY expensive proposition, from Jupiter's
> gravity well.
A NASA Ames group proposed the "Europa Ice Clipper" a couple of years ago.
Send a copy of the Stardust probe on a flyby of Europa. Release a
cannonball just before the flyby, aimed to impact Europa just ahead of the
spacecraft. The collision produces a plume of impact debris and gases, and
the spacecraft grabs some as it flies through.
Expensive compared to Stardust, cheap compared to a lander that returns
samples. Audacious, and has a number of technical problems, but might be
worth trying. Keith Cowing has a page for it at
<http://www2.astrobiology.com/astro/europa/ice.clipper.html>.
> Several other people have already posted the concept of using a
> radioisotope thermal generator (RTG) to melt through the ice. I seem to
> recall that this idea originated at JPL, but at the moment I can't locate
> any references to it. Anyone?
You're probably thinking of the "hydrobot" submarine proposed by Joan
Horvath and her group. See
<http://www-b.jpl.nasa.gov/pictures/tech/hydrobot.html> and also
<http://www.flatoday.com/space/explore/stories/1997/041297b.htm>.
The melting-descent technique is similar to one posed in 1961 by William
Manchester Adams, as I mentioned in another posting.
There's a Europa Orbiter page, also at JPL, at
<http://www.jpl.nasa.gov/ice_fire//europao.htm>.
The new COMPLEX report, *A Science Strategy for the Exploration of Europa*,
is at <http://www.nationalacademies.org/ssb/comp-europamenu.htm>.
Keith Cowing's Astrobiology Web has a Europa page with pointers to a lot
more information at <http://www2.astrobiology.com/astro/europa/index.html>.
And, of course, there are dozens of pictures of Europa available from the
Galileo orbiter, whose homepage is at <http://www.jpl.nasa.gov/galileo/>.
--
Bill Higgins | Make Money Fast!
Fermilab | See
HIG...@FNAL.FNAL.GOV | <ftp://www.treasury.gov/currency/100.ps>
Patrick & Sangeeta Bishop
Mike Williams wrote:
> Wasn't it Chris who wrote:
> >At first I thought "laser"! Just use a laser to drill through the ice. But
> >this would require a power source probably the size of your drilling rig.
> >So then I thought "big magnifying glass". If you could make a large but
> >collapsible magnifying glass out of composite plastics and put it into a
> >stationary orbit (This is the tricky part I think) between the sun and
> >Europa you could let the sun drill the hole for you.
> >The giant lens could be created similar to a breast implant shaped like a
> >lens rather than a boob. A huge plastic bag filled with water harvested from
> >the moon.
>
> The problem with any solution like that is that you have to find a way
> to get the heat down through 60 miles of ice. Ice and water aren't
> sufficiently transparent for lasers or concentrated sunlight to work
> (see how dark it is at the bottom of our own oceans, and that's only a
> few miles of water).
>
> A much easier way is to take a nuclear power pack, like what they use
> for most deep space missions but perhaps a bit beefier, and just use it
> to keep the drilling bit warm enough to melt a little bit of ice
> immediately around it. So at any instant, there's only a small melted
> pocket surrounding the bit. On the top side of the bit there'd be a 60
> mile coil of wire which unravels as the bit descends. The ice refreezes
> around the uncoiled wire as the bit descends. The wire carries commands
> and data to and from a surface module which relays the data back to
> Earth.
>
> --
> Mike Williams + #
> Gentleman of Leisure
You're on to something Mike. But it might not be necessary to worry about the
melted water refreezing around the coil. With the small amount of ice that would
be melted at a time, it might be more likely that the water would turn into a gas
almost as soon as it turned liquid owing to the zero atmospheric pressure at the
surface.
Patrick
Matthew Montchalin
|On 13 Jan 2000, John Rehling wrote:
|> Something that melts down to the ocean is a nice idea, though if the
|> crust is not pure ice, it may not be so easy.
|
|The crust is probably fairly pure, or it wouldn't have such a high albedo. I
|don't think there are a lot of silicates mixed in with it, if that's what
|you're thinking.
If there is some kind of algae/microbial life milling about in the ocean
below, wouldn't you suppose that some kind of depositional process be
responsible for a lot of impurities in the crust? Now, seeing as how
Europa has a high albedo, there must not be that many impurities making
it up to the surface. Except where all those cracks are. Hmmm... And
the cracks look a little darker than the rest of the surface...
Matthew Montchalin
|You're on to something Mike. But it might not be necessary to worry
|about the melted water refreezing around the coil. With the small
|amount of ice that would be melted at a time, it might be more likely
|that the water would turn into a gas almost as soon as it turned liquid
|owing to the zero atmospheric pressure at the surface.
Doesn't ordinary H2O ice 'boil' in a vacuum? Or is that a truism?
Matthew Montchalin
On Thu, 13 Jan 2000, Bill Higgins-- Beam Jockey wrote:
|spaghetti, probably lend themselves to constructing stratigraphic sequences,
|at least on a local scale. So patient photogeologists may be able to
|construct a partial "story" for Europa's surface long before any spacecraft
|lands there. They can recommend the best places to look.
What was the earliest history of Europa like?
If it ever had an atmosphere, when did it lose it? How long has it been
in orbit around Jupiter? Did it accrete in place?
I'd love to see some computer models of the formation of Europa, even if
only of its recent history, and how the surface flexes about on a regular
(?) basis, cracking and spewing its ocean upwards... As for thermal
imaging of Europa, are the cracks warmer than other parts of Europa?
Jason Clayton
Matthew Montchalin <mmon...@OregonVOS.net> wrote in message
news:Pine.SUN.3.96.100011...@compass.oregonvos.net...
> On Wed, 12 Jan 2000, DaveKa wrote:
>
> |You wouldn't need to drill. Just a probe that would heat up and melt
> |through the ice down to the liquid ocean.
>
Matthew Montchalin
|Assuming they left hard parts that were preserved.
It would indeed be nice if there were 'hard parts' that floated to the
top, and somehow got mixed up with the icy crust, and sooner or later
ejected into an ice plume that rises into a crustal crack, but even if it
is just 'soft stuff' that rises up, there ought to be ways of analyzing
the remains and concluding that it represents either life, or waste
products of life.
John Rehling
> don't think there are a lot of silicates mixed in with it, if that's what
> you're thinking.
What I'm thinking is that if it's 99% pure, and you need to melt
through 10km of ice, that's still 100m of other stuff in your
way. Maybe it'll slide right out of your way, but I'd hate to have a
once-in-20-years kind of probe stuck half way down.
-JAR
--
Life does not cease to be funny when people die any more than it
ceases to be serious when people laugh.
-G.B. Shaw
Richard Hendricks
ice melts, it would tend to collect near the bottom of the well.
Wouldn't this clog up or prevent the heat drill from working properly?
It would be like the moraine from a glacier, as the stuff embedded in
the ice you have melted through travels down the column with you. Or
would it?
Jan Panteltje
>> A much easier way is to take a nuclear power pack, like what they use
>> for most deep space missions but perhaps a bit beefier, and just use it
>> to keep the drilling bit warm enough to melt a little bit of ice
>> immediately around it. So at any instant, there's only a small melted
>> pocket surrounding the bit. On the top side of the bit there'd be a 60
>> mile coil of wire which unravels as the bit descends. The ice refreezes
>> around the uncoiled wire as the bit descends. The wire carries commands
>> and data to and from a surface module which relays the data back to
>> Earth.
I like the idea though.
Think I would look for penquins ;-)
Jan
John Rehling
trying to get to an ocean, but it's entirely possible that the crust
is older than biology, even if there is any. Some estimates of the age
of the Europan crust are up to 3 GYA. It's entirely possible that
there is life down there, but that it evolved with kilometers of ice
already in place above it.
-JAR
--
Ecologists believe that a bird in the bush is worth two in the hand.
-Stanley C. Pearson
Matthew Montchalin
|Biological studies of the ice are worthwhile, and much easier than
|trying to get to an ocean, but it's entirely possible that the crust
|is older than biology, even if there is any. Some estimates of the age
|of the Europan crust are up to 3 GYA. It's entirely possible that
|there is life down there, but that it evolved with kilometers of ice
|already in place above it.
How long does it take an ice plume to travel from the bottom of the crust
to the top of the crust?
Mike Williams
>
>
>Mike Williams wrote:
>
>> Wasn't it Chris who wrote:
>> >At first I thought "laser"! Just use a laser to drill through the ice. But
>> >this would require a power source probably the size of your drilling rig.
>> >So then I thought "big magnifying glass". If you could make a large but
>> >collapsible magnifying glass out of composite plastics and put it into a
>> >stationary orbit (This is the tricky part I think) between the sun and
>> >Europa you could let the sun drill the hole for you.
>> >The giant lens could be created similar to a breast implant shaped like a
>> >lens rather than a boob. A huge plastic bag filled with water harvested from
>> >the moon.
>>
>> The problem with any solution like that is that you have to find a way
>> to get the heat down through 60 miles of ice. Ice and water aren't
>> sufficiently transparent for lasers or concentrated sunlight to work
>> (see how dark it is at the bottom of our own oceans, and that's only a
>> few miles of water).
>>
>> for most deep space missions but perhaps a bit beefier, and just use it
>> to keep the drilling bit warm enough to melt a little bit of ice
>> immediately around it. So at any instant, there's only a small melted
>> pocket surrounding the bit. On the top side of the bit there'd be a 60
>> mile coil of wire which unravels as the bit descends. The ice refreezes
>> around the uncoiled wire as the bit descends. The wire carries commands
>> and data to and from a surface module which relays the data back to
>> Earth.
>>
>melted water refreezing around the coil. With the small amount of ice that
>would
>be melted at a time, it might be more likely that the water would turn into a
>gas
>almost as soon as it turned liquid owing to the zero atmospheric pressure at the
>surface.
Good point, but it wouldn't stay gaseous very long. By the time the gas
had diffused up the hole for a short distance it would all solidify
again when it contacts the cold sides of the shaft. If you look at how
easily steam from a kettle condenses on a cold plate, you might get an
idea of how quickly the refreezing vapour would plug up a super-cold
shaft. Once the hole is sealed above the probe, further advances
increase the vapour pressure inside the shaft to the point where liquid
water is possible.
John Rehling
> to the top of the crust?
Depends upon what's happening underneath. Potentially not so
long. Potentially, it may never happen at all.
-JAR
--
Le hasard c'est peut-etre le pseudonyme de Dieu, quand il ne veut pas
signer.
-Jacques Anatole Francois Thibault
Alex R. Blackwell
John Rehling wrote:
>
> > How long does it take an ice plume to travel from the bottom of the crust
> > to the top of the crust?
>
> Depends upon what's happening underneath. Potentially not so
> long. Potentially, it may never happen at all.
>
This reminds me of President Reagan's answer to a reporter's question
about the U.S. stock market. Paraphrasing Reagan, "It could go up, or
down, or not change at all."
--
Alex R. Blackwell
E-mail: ablac...@co.honolulu.hi.us
Eric McDaniel
"Mike Williams" <mi...@nospam.please> wrote in message
news:9IpYdDAS...@econym.demon.co.uk...
> Good point, but it wouldn't stay gaseous very long. By the time the gas
> had diffused up the hole for a short distance it would all solidify
> again when it contacts the cold sides of the shaft. If you look at how
> easily steam from a kettle condenses on a cold plate, you might get an
> idea of how quickly the refreezing vapour would plug up a super-cold
> shaft. Once the hole is sealed above the probe, further advances
> increase the vapour pressure inside the shaft to the point where liquid
> water is possible.
>
Doesn't Europa experience some nasty tidal forces? The shifting,
cracking ice might crush the probe before it got very far down anyway.
Matthew Montchalin
Alex R. Blackwell wrote:
|John Rehling wrote:
|> > How long does it take an ice plume to travel from the bottom of the
|> > crust to the top of the crust?
|>
|> Depends upon what's happening underneath. Potentially not so
|> long. Potentially, it may never happen at all.
|
|This reminds me of President Reagan's answer to a reporter's question
|about the U.S. stock market. Paraphrasing Reagan, "It could go up,
|or down, or not change at all."
The important thing is that thermal imaging from an orbital observer may,
in combination with seismometer-bots, help answer the question.
Someone suggested oceans that are 60 miles deep. Another suggested the
possibility that the ice actually rides directly on rock, and if there
are bodies of liquid water, they are not continuous in the sense of a
single 'ocean.' An orbiter will indicate just how high the tides go in
Europa, and whether the ice floats on a single body of water, or whether
different 'sections' of Europa move more or less independently from one
another.
(Say, if huge ice blocks are deformed enough, they crack. Do they also
generate electrical discharges when they crack?)
Matthew Montchalin
Very Good point! (If Mother Nature cares about her little experiment
inside of Europa, then she also has a number of means at her disposal
to keep us from screwing with it too much. Perhaps a surface observatory
will suit humanity well for a few hundred years, at least until we have
scoped out a very stable and suitable piece of the crust to dig into?)
Bill Higgins-- Beam Jockey
> Eric McDaniel wrote:
> |"Mike Williams" <mi...@nospam.please> wrote in message
> |news:9IpYdDAS...@econym.demon.co.uk...
> |> Good point, but it wouldn't stay gaseous very long. By the time the gas
> |> had diffused up the hole for a short distance it would all solidify
> |> again when it contacts the cold sides of the shaft. If you look at
> |> how easily steam from a kettle condenses on a cold plate, you might
> |> get an idea of how quickly the refreezing vapour would plug up a
> |> super-cold shaft. Once the hole is sealed above the probe, further
> |> advances increase the vapour pressure inside the shaft to the point
> |> where liquid water is possible.
> |
> |Doesn't Europa experience some nasty tidal forces? The shifting,
> |cracking ice might crush the probe before it got very far down anyway.
The ice will move pretty slowly. The hot probe will, I think, be surrounded
by a bubble of liquid water and vapor, which will tend to alleviate this
problem.
But getting a signal out to the surface will probably depend upon unreeling
a cable behind the descending probe. Cables running throgh ice are often
snapped by stresses in terrestrial Arctic experiments; designing a cable
that can survive Europan conditions will be a challenge.
> > Very Good point! (If Mother Nature cares about her little experiment
> inside of Europa, then she also has a number of means at her disposal
> to keep us from screwing with it too much. Perhaps a surface observatory
> will suit humanity well for a few hundred years, at least until we have
> scoped out a very stable and suitable piece of the crust to dig into?)
Too pessimistic. These problems can be solved with sheer determination and
plenty of money.
Maybe we can design a signal cable to pay out in a survivable way.
Maybe we can use radio signals of some wavelength to get a low-bandwidth
signal through the ice.
Maybe we can drop a chain of radio (or sonar?) relays at various levels
behind the probe.
Maybe the probe can melt its way down, take data, then drop most of its mass
and melt its way back UP through the ice, carrying only a CD-ROM for
recovery on the surface.
--
She was only a | Bill Higgins
rocket scientist's daughter, | Fermilab
but she left the boys | Internet: hig...@fnal.fnal.gov
exhausted behind her. | Bitnet: Sic transit gloria mundi
Bill Higgins-- Beam Jockey
> John Rehling wrote:
> >
> > What I'm thinking is that if it's 99% pure, and you need to melt
> > through 10km of ice, that's still 100m of other stuff in your
> > way. Maybe it'll slide right out of your way, but I'd hate to have a
> > once-in-20-years kind of probe stuck half way down.
>
> Good point. What if the material was just small sand or dust? As the
> ice melts, it would tend to collect near the bottom of the well.
> Wouldn't this clog up or prevent the heat drill from working properly?
> It would be like the moraine from a glacier, as the stuff embedded in
> the ice you have melted through travels down the column with you. Or
> would it?
This is an issue that demands some research here on Earth: make up some
"sandy ice" at 100 K in the lab, and see what happens when a simulated
Europa probe tries to penetrate it.
After the hole closes behind it, the probe will be in a region of liquid
water and some vapor surrounded by ice. Since the outside of the probe will
be several hundred degrees hotter than the ice, I expect there will be lots
of convection in the water, enough to stir up any silt that accumulates-- as
long as there's not much of it.
If we build up a *thick* layer of sand or silt, and it begins to insulate
the ice below from efficient heating, the effect will be to make the hole
*wider* as the probe's vertical motion slows down and more heat goes into
the sides.
Could the descent rate actually go to zero? If so, we can design the probe
to have mechanical digging or boring apparatus to get itself out of this
embarrassing situation. This messes up the elegant idea of a descent
vehicle with no moving parts, but seems quite achievable.
Ideally, you'd design gadgets to deposit silt and sand above the vehicle,
into the re-frozen plug of ice it leaves behind, or sideways into the ring
of ice around the vehicle.
A way to move the stalled probe sideways, leaving a bowl of silt behind and
starting a new, offset, low-silt shaft in the widened "slowdown" hole, might
be another solution. Pistons that shove the probe against one side of the
hole could do the job.
Hiram Berry
[...]
> >> The problem with any solution like that is that you have to find a way
> >> to get the heat down through 60 miles of ice. Ice and water aren't
> >> sufficiently transparent for lasers or concentrated sunlight to work
> >> (see how dark it is at the bottom of our own oceans, and that's only a
> >> few miles of water).
How do you get the estimate of 60 miles thick? Is it from
radiation/absorption measurements of the Europan surface in the IR coupled
with a hypothetical thermal flow model of the crust?
Just curious,
Hiram Berry
Mike Williams
>>>
>>> A much easier way is to take a nuclear power pack, like what they use
>>> for most deep space missions but perhaps a bit beefier, and just use it
>>> to keep the drilling bit warm enough to melt a little bit of ice
>>> immediately around it. So at any instant, there's only a small melted
>>> pocket surrounding the bit. On the top side of the bit there'd be a 60
>>> mile coil of wire which unravels as the bit descends. The ice refreezes
>>> around the uncoiled wire as the bit descends. The wire carries commands
>>> and data to and from a surface module which relays the data back to
>>> Earth.
>I like the idea though.
That's no problem. Once the wire has uncoiled from the back of the
drilling bit you don't ever want it to move any more. The current
section of the wire freezes to the ice, but then the bit uncoils some
more from the coil that's kept within the melted pocket.
There's a danger that icequakes and glacial movements might snap the
wire, so it would have to be made of something that was quite stretchy
at very low temperatures. And there's another danger that there might be
the occasional chunk of rock (such as an old meteorite) in the way.
Tom
>
> > A much easier way is to take a nuclear power pack, like what they use
> > for most deep space missions but perhaps a bit beefier, and just use it
> > to keep the drilling bit warm enough to melt a little bit of ice
> > immediately around it. So at any instant, there's only a small melted
> > pocket surrounding the bit. On the top side of the bit there'd be a 60
> > mile coil of wire which unravels as the bit descends. The ice refreezes
> > around the uncoiled wire as the bit descends. The wire carries commands
> > and data to and from a surface module which relays the data back to
> > Earth.
> >
> > Mike Williams + #
> > Gentleman of Leisure
>
> melted water refreezing around the coil. With the small amount of ice that would
> be melted at a time, it might be more likely that the water would turn into a gas
> almost as soon as it turned liquid owing to the zero atmospheric pressure at the
> surface.
When that thing hits the bottom of the ice you're going to have one hell
of a backpressure surge due to the overburden of ice on the liquid
water. (This happens all the time with oil wells and can utterly crush
drilling equipment). 60 miles at 1/6g or so would be like the pressure
10 miles under the water surface here (if the oceans went that far) -
about 23,000 psi. If the hole you left is open to space, you're going to
have your probe spit back out into space at one hell of a velocity.
Ohhh... Heyyyy... I smell a possible way to send a sample back towards
Earth.
christronomy
ingenuity out there! I hope NASA is reading. However as far as designing
durable cables, good luck. I'm in the sub service. Subs tow towed arrays,
which cost millions of dollars each. The toe cable is about the size of
coaxil cable and made with a titanium sheath, but we still lose them all the
time. And all the navy's engineers can't save the towed array!????
"Bill Higgins-- Beam Jockey" <hig...@fnal.gov> wrote in message
news:Pine.SGI.4.05.100011...@fsgi02.fnal.gov...
>
Paul Morris
> "Jason Clayton" <jaso...@comwerx.net> wrote in message
> news:mtUe4.820$9T4....@nnrp2.rcsntx.swbell.net...
> >
> > I know I am going to really hear from the anti-nuke crowd, but let's just
> > borrow some ideas from Edward Teller (Father of the U.S. H-bomb and
> advocate
> > of it's use as an earth-mover). What if we were to take a few of those
> > nasty little (about 10 megatons) h-bombs leftover from the cold war and
> > create a hole big enough to spew out some material into space that could
> > then be analyzed by an orbiting spacecraft? I know the idea sounds
> > ridiculous at first, but given our current track record for landing
> complex
> > missions that have too many things that can fail, and a dwindling NASA
> space
> > science budget, the idea starts to lend itself some creedance. Yes, if
> > there was a local ecosystem there (be a little far from the surface to use
> > photosynthesis as a food source, but who knows) it would very much disturb
> > it, but I don't suppose it could be any more populated than the Nevada
> > Desert, Siberia, or the South Pacific. If anyone has any other ideas on
> how
> > to go about exploring Europa (or know of any really good websites) I would
> > be interested in hearing them.
That would be a violation of the Nuclear Test Ban Treaty,
of which the U.S. is a signatory. It prohibits explosions in
"outer space" among other things.
--
Email: lastname at best dot com. (no spam please)
Mike Williams
>Maybe the probe can melt its way down, take data, then drop most of its mass
>and melt its way back UP through the ice, carrying only a CD-ROM for
>recovery on the surface.
That's looking promising. However, there'd be a distinct possibility
that it wouldn't manage to melt its way exactly back up the original
track, and over 60 miles there might be a considerable sideways drift.
So, you either need a pretty sophisticated rover to do the retrieval, or
get the surfacer to radio the data to the base station or orbiter,
rather than retrieve it.
Mike Williams
That's what the NASA article that started this thread was all about, see
Message-ID: <11JAN200...@kelvin.jpl.nasa.gov>
Subject: Galileo Findings Boost Idea Of Other-Worldly Ocean On Europa
Jan Panteltje
>>>>
>>>> A much easier way is to take a nuclear power pack, like what they use
>>>> for most deep space missions but perhaps a bit beefier, and just use it
>>>> to keep the drilling bit warm enough to melt a little bit of ice
>>>> immediately around it. So at any instant, there's only a small melted
>>>> pocket surrounding the bit. On the top side of the bit there'd be a 60
>>>> mile coil of wire which unravels as the bit descends. The ice refreezes
>>>> around the uncoiled wire as the bit descends. The wire carries commands
>>>> and data to and from a surface module which relays the data back to
>>>> Earth.
>>I like the idea though.
>
>That's no problem. Once the wire has uncoiled from the back of the
>drilling bit you don't ever want it to move any more. The current
>section of the wire freezes to the ice, but then the bit uncoils some
>more from the coil that's kept within the melted pocket.
>
>There's a danger that icequakes and glacial movements might snap the
>wire, so it would have to be made of something that was quite stretchy
>at very low temperatures. And there's another danger that there might be
>the occasional chunk of rock (such as an old meteorite) in the way.
>
>Mike Williams + #
>Gentleman of Leisure
>
Wonder if radio or sonar or perhaps even lasers could be used to communicate
with the surface station.
Sound waved travel fast trough water, but ice I do not know?
60 miles of cable is a lot, I have a 100 meter reel somewhere, it is heavy!
Jan
Steve & Bonnie Glasgow
Mike Williams wrote in message ...
><snip>the ice refreezes
>around the uncoiled wire as the bit descends. The wire carries commands
>and data to and from a surface module which relays the data back to
>Earth.
>
how will the bit descend if the ice refreezes around the uncoiled wire?
seems the friction will prevent the descent beyond an inadequate limit.
Dale Firmin
Steve & Bonnie Glasgow wrote:
> Mike Williams wrote in message ...
> ><snip>the ice refreezes
> >around the uncoiled wire as the bit descends. The wire carries commands
> >and data to and from a surface module which relays the data back to
> >Earth.
> >
>
> how will the bit descend if the ice refreezes around the uncoiled wire?
> seems the friction will prevent the descent beyond an inadequate limit.
If I can answer for him, I see what he is saying. The coil is carried with
the warm bit. The refreezing will be around the uncoiled wire above it.
The bit can continue to descend uncoiling wire from the coil it is carrying
with it. Sixty miles of wire is a lot but not unreasonable.
It's kind of like the military's wire guided antitank missiles, if you were
in the military. Wire coils out of the tail of the missile as the missile
flies and course corrections are transmitted down the wire to the missile
guiding it to target.
Communication could probably also be carried out using VLF radio waves which
penetrate water quite well and are used to communicate to submarines but VLF
antennas are a problem in that an efficient antenna is extremely large, not
too large for a surface receiver but unrealistic for a bit. Perhaps it
don't have to be that efficient in the more radio quiet europa than it does
on the radio noisy earth. I think that the wire would be a better choice.
Dale
Frank Crary
Mike Williams <mi...@econym.demon.co.uk> wrote:
>>> >> The problem with any solution like that is that you have to find a way
>>> >> to get the heat down through 60 miles of ice. Ice and water aren't
>>> >> sufficiently transparent for lasers or concentrated sunlight to work
>>> >> (see how dark it is at the bottom of our own oceans, and that's only a
>>> >> few miles of water).
>>How do you get the estimate of 60 miles thick? Is it from
>>radiation/absorption measurements of the Europan surface in the IR coupled
>>with a hypothetical thermal flow model of the crust?
>That's what the NASA article that started this thread was all about, see
>Message-ID: <11JAN200...@kelvin.jpl.nasa.gov>
>Subject: Galileo Findings Boost Idea Of Other-Worldly Ocean On Europa
Although the press report didn't really mention it, that number is
very uncertain. Basically the Galileo magnetometer has measured a
magnetic field which matches what you would expect from induced
currents in a conductive layer near Europa's surface. The only
sort of conductive layer anyone can think of is a salty ocean
below the surface. (Trust me on that: I've wasted a decent amount
of time trying to find alternatives, and nothing plausible even
comes close to working.) So they assume that means it's evidence
of an ocean. One problem with that is the similar magnetic field
signature observed at Callisto. So either Callisto has an ocean
as well (weird, given its surface geology and expected thermal
structure) or there is some other way to produce this signature
(in which case the signature might not mean an ocean inside
Europa.) But even if you assume the signature is from an ocean,
the depth of the ocean is quite uncertain. The strength of the
signature depends on how deep, thick and salty the ocean is.
There are a wide range of possible combinations that could
account for the observations, since we have no idea how thick
or salty the ocean might be. Christoph Zimmer, on the Galileo
magnetometer team, has noted that the induced currents would
also produce higher order terms in the magnetic field, and
that might let you pin down the depth, thickness and conductivity
of an ocean. But this would require a magnetometer on an orbiter:
The Galileo data isn't really enough to measure more than the
induced dipole term.
Frank Crary
lad...@my-deja.com
j...@panteltje.demon.nl (Jan Panteltje) wrote:
> I think (since you are a biologist) the suggestion of looking for
> 'right handed' molucules (or was it left handed ;))
The word that chemists use is "chiral," rather than "handed."
Let's just confine our discussion to amino acids for the moment, though
there are many other types of "organic" molecules found off of the Earth.
Nearly all of the amino acids found in living organisms on Earth are of a
single chirality, defined as "D-" for "dextro-," or "right-handed." But
biochemists have constructed structurally sound, functional proteins
using only synthetic "left-handed"/"levo-"/"L-" amino acids. Mixtures of
the two types of amino acids, however, do not work.
It appears that life can operate with either D- or L-amino acids. The
only requirement for protein folding, as we understand it, is that the
amino acids be consistent -- all L, or all D. Earth just "chose" D.
However, there may be way of assembling catalytically-active molecules
from a mixture of amino acids that we DON'T understand. Furthermore, if
you find an equal mixture of L- and D-amino acids in a sample, this
doesn't mean that there's no life there. An organism might have the
means to sort the two types. Therefore, a "negative" result (no chiral
bias) is not very conclusive.
It gets worse. A few years ago, I couldn't have imagined any process,
other than life, by which amino acids in space could develop a chiral
bias. But chemistry experiments here on Earth have shown that circularly
polarized light can influence stereochemical reactions. And strong
circularly polarized light has recently been observed in interstellar
nebulae:
http://www.sciencemag.org/cgi/content/abstract/281/5377/672
Therefore, a "positive" result (some chiral bias) is also inconclusive!
In light of these recently-revealed weaknesses, I don't believe that the
chirality test is a good one. Perhaps if there were a STRONG chiral
asymmetry, this result would provide useful corroboration for another
test.
> or something,
> that was done by the same persons that designed the experiment on
> the first mars probe, that was POSITIVE, would give an indication
> of life?
I'm not aware that the Viking probe included a test for amino acid
chirality. I do recall a test in which radioactively-labeled organic
compounds were added to the Martian soil. The test was to look for the
appearance of the label in other compounds, which would suggest metabolic
processes. IIRC, a positive result was obtained, but was then duplicated
on Earth using non-living zeolite clays.
The Murchison meteorite showed a modest excess of L-amino acids. Are you
thinking of this study?
Chemistry is powerful stuff, but I still want a microscope on the Europa
Sea Explorer.
> The following URL may be also of interest to you:
> www.spie.org/web/abstracts/3100/3111.htm
Your link didn't work -- I got an error message from SPIE.
--
John J. Ladasky Jr., Ph.D.
Department of Structural Biology
Stanford University Medical Center
Stanford, CA 94305
Secretary, Californians for Renewable Energy <http://www.calfree.com>
Sent via Deja.com http://www.deja.com/
Before you buy.
lad...@my-deja.com
Bill Higgins-- Beam Jockey <hig...@fnal.gov> wrote:
> On Thu, 13 Jan 2000 lad...@my-deja.com wrote:
>
> > Would you attempt to physically retrieve some of the debris, say
> > with an aerogel as is being done with the Stardust probe? How much
> > material can you realistically expect to harvest? What might the
> > explosion have done to the material? And how would you analyze it?
> > Stardust is bringing its samples back to Earth -- a VERY expensive
> > proposition, from Jupiter's gravity well.
>
> A NASA Ames group proposed the "Europa Ice Clipper" a couple of years
> ago. Send a copy of the Stardust probe on a flyby of Europa. Re-
> lease a cannonball just before the flyby, aimed to impact Europa just
> ahead of the spacecraft. The collision produces a plume of impact
> debris and gases, and the spacecraft grabs some as it flies through.
>
> Expensive compared to Stardust, cheap compared to a lander that re-
> turns samples. Audacious, and has a number of technical problems,
> but might be worth trying. Keith Cowing has a page for it at
> <http://www2.astrobiology.com/astro/europa/ice.clipper.html>.
This is cool, in a Rube Goldberg/Mars Pathfinder sort of way. But their
mathematical analysis of the particulate collection says that they only
expect to collect seventy particles, with an average diameter of 1
micrometer and an upper limit of 100 micrometers. It would be a sample
of material from another planet, and thus hardly insignificant. However,
such a meager sample would probably not reveal any signs of life from
Earth's surface ice that anyone would believe. You would be forced to do
nano-scale chemistry and atomic microscopy, and then make tenuous
inferences from your results. These are exactly the kinds of studies
that were done on the Martian meteorite ALH 84001, studies that have seen
no end of controversy and criticism.
> > Several other people have already posted the concept of using a
> > radioisotope thermal generator (RTG) to melt through the ice. I
> > seem to recall that this idea originated at JPL, but at the moment
> > I can't locate any references to it. Anyone?
>
> You're probably thinking of the "hydrobot" submarine proposed by Joan
> Horvath and her group. See
> <http://www-b.jpl.nasa.gov/pictures/tech/hydrobot.html> and also
> <http://www.flatoday.com/space/explore/stories/1997/041297b.htm>.
>
> The melting-descent technique is similar to one posed in 1961 by
> William Manchester Adams, as I mentioned in another posting.
Yes, that's it. Thanks!
[snip remainder]
Nigel Danton
Bill Higgins-- Beam Jockey <hig...@fnal.gov> writes
>A committee of scientists has just published a new report planning the
>exploration of Europa. See
><http://www.nationalacademies.org/ssb/comp-europamenu.htm>.
That url is restricted access, is the report available anywhere else?
Thanks
--
Nige Danton
Lance Purple
> Communication could probably also be carried out using VLF
> radio waves which penetrate water quite well and are used to
> communicate to submarines but VLF antennas are a problem in
> that an efficient antenna is extremely large, not too large
> for a surface receiver but unrealistic for a bit.
Instead of the diver having to unreel 60 km of optical fiber
to stay connected with a surface relay, maybe it'd be easier
to let it sink through the ice and the water until it reaches
the sea bottom; then deploy a few km of VLF antenna wire with
a float. Meanwhile, instead of a surface relay, have a Europa
orbiter that trails another VLF antenna wire.
--
,--------------------------------------------,
| Lance Purple (lpurple at netcom dot com) |
'--------------------------------------------'
Matthew Montchalin
I doubt there will be much surprising stuff to find in the report; maybe
someone can strip out the HTML/MIME crap and post it here on Usenet
somewhere?
(Sending an orbital surveyor to Europa seems to be the most reasonable
thing to advocate, at least for the next five or six years. Beyond
that, seismometer-bots and rovers.)
Matthew Montchalin
|Dale Firmin <da...@bellsouth.net> wrote:
|
|> Communication could probably also be carried out using VLF
|> radio waves which penetrate water quite well and are used to
|> communicate to submarines but VLF antennas are a problem in
|> that an efficient antenna is extremely large, not too large
|> for a surface receiver but unrealistic for a bit.
|
|Instead of the diver having to unreel 60 km of optical fiber
|to stay connected with a surface relay, maybe it'd be easier
|to let it sink through the ice and the water until it reaches
|the sea bottom;
How expensive will these 'sinker' probes be, anyway? I can see
putting a couple orbital surveyors up in orbit around Europa,
and a handful of seismometer-bots on its surface, and maybe even
a rover or two, but the 'sinker-probes' seem to be the most expensive
things to send to Europa... I doubt that we will have 'sinker-probes'
sent there for upwards of a hundred years...
|then deploy a few km of VLF antenna wire with a float. Meanwhile,
|instead of a surface relay, have a Europa orbiter that trails another
|VLF antenna wire.
Why do the 'sinker-probes' need big antennas, anyway? Couldn't the
seismometer-bots have big parabolic dishes, instead? The purpose of
the antennas is merely to receive data?
Richard Hendricks
would cause such a drag on a probe it would be difficult to manage.
Didn't NASA do experiments with using a ribbon of wire to drag
satellites out of Earth orbit?
Lance Purple wrote:
>
> Dale Firmin <da...@bellsouth.net> wrote:
>
> > Communication could probably also be carried out using VLF
> > radio waves which penetrate water quite well and are used to
> > communicate to submarines but VLF antennas are a problem in
> > that an efficient antenna is extremely large, not too large
> > for a surface receiver but unrealistic for a bit.
>
> Instead of the diver having to unreel 60 km of optical fiber
> to stay connected with a surface relay, maybe it'd be easier
> to let it sink through the ice and the water until it reaches
> the sea bottom; then deploy a few km of VLF antenna wire with
> a float. Meanwhile, instead of a surface relay, have a Europa
> orbiter that trails another VLF antenna wire.
>
Tom
>
> |Instead of the diver having to unreel 60 km of optical fiber
> |to stay connected with a surface relay, maybe it'd be easier
> |to let it sink through the ice and the water until it reaches
> |the sea bottom;
> |then deploy a few km of VLF antenna wire with a float. Meanwhile,
> |instead of a surface relay, have a Europa orbiter that trails another
> |VLF antenna wire.
>
> seismometer-bots have big parabolic dishes, instead? The purpose of
> the antennas is merely to receive data?
Why not just have the surface relay use Geophones (EuropaPhones?)?
They have sound detectors all over the Earth designed to detect the
passing of Submarines. When a nuke sub sank many years ago in the
eastern Atlantic, such detectors as far away as New York detected 17
"Concussion Events" as various things imploded during the sub's death
plunge. Just put a Thumper on the sinker probe to thump out messages
back to the surface.
Dale Firmin
Matthew Montchalin wrote:
<snip>
> |then deploy a few km of VLF antenna wire with a float. Meanwhile,
> |instead of a surface relay, have a Europa orbiter that trails another
> |VLF antenna wire.
>
> Why do the 'sinker-probes' need big antennas, anyway? Couldn't the
> seismometer-bots have big parabolic dishes, instead? The purpose of
> the antennas is merely to receive data?
I brought up the VLF so I'll tackle that one. To be efficient, an antenna
has to be electrically as long as the wavelength. This means that the
antenna has to be physically longer for longer wavelengths (lower
frequency) or have circuits to match the frequency. Matching circuits are
less efficient so the best way to go is long antennas. VLF has
wavelengths of miles. This means the antennas need to be very long to be
efficient even if they do have matching circuits.
Dishes are great for short wavelengths but you would need a dish miles in
diameter for VLF. When the frequency becomes lower, you can get more gain
by using another type antenna. The television antenna on your house (the
old fashion outdoor type) is a Yagi named after it's inventor. Gain is
increased simply by adding more elements. (Your TV antenna is actually a
log periodic Yagi which increases its bandwidth which has a tendency to
narrow when you try to increase gain. You want to catch ALL the
channels.) Another type of antenna is a dipole --- two wires in opposite
direction, or one wire grounded --- more appropriate for VLF. (A Yagi is
simply a dipole with reflectors and directors (elements) to increase
gain.) You can increase gain in a grounded dipole by using a very long
wire of several wavelengths. So a surface relay could simply throw out an
insulted wire in two directions of a mile or more or one long wire in one
direction and ground the other end to the ice. The sinker probe could
then float a very long wire after it reaches (hopefully) liquid.
The problem with the sinker probe using VLF is it would not be able to
string along the very long wire antenna while it sinks. It would be out
of communication until it hit liquid (if it ever hits liquid). If it
never hits liquid, its antenna is never deployed and all we get is
silence. Just like the latest Mars probe we could never know why.
As for the VLF relay to an orbiter, I think that is a worst idea. Imagine
the voltages generated in a wire of a mile or several miles long passing
through the strong magnetic fields of Jupiter. The noise alone would be
too much if it didn't fry. Remember that Jupiter is the second strongest
radio object in our solar system and can easily be detected from earth
with simply an old television antenna.
I feel that uhf or microwaves from a surface relay is better to relay to
an orbiter due to noise and the smaller antenna requirements. Wire or
optical fiber to the sinker probe would allow continuous progress
monitoring. If there is no ocean underneath, the wire/fiber guided probe
could tell us that where the VLF probe would only remain silent.
Dale
Mike Williams
>How expensive will these 'sinker' probes be, anyway? I can see
>putting a couple orbital surveyors up in orbit around Europa,
>and a handful of seismometer-bots on its surface, and maybe even
>a rover or two, but the 'sinker-probes' seem to be the most expensive
>things to send to Europa... I doubt that we will have 'sinker-probes'
>sent there for upwards of a hundred years...
Cheaper than ISS, and with a better chance of scientific results and
popular appeal. If such a probe does find microbes, particularly if
their chemistry indicates that they are unrelated to Earth life, then
that would lend considerable weight to the hypothesis that life abounds
wherever there is liquid water. This would have a considerable effect on
the support for projects like TPF and Seti.
>Why do the 'sinker-probes' need big antennas, anyway? Couldn't the
>seismometer-bots have big parabolic dishes, instead? The purpose of
>the antennas is merely to receive data?
The VLF antenna was a suggestion for an alternative to using a cable to
get the data from the sinker to a relay above the ice. Parabolic dishes
of moderate size don't work very well for VLF radio - they're not much
good if the dish diameter is less than the wavelength - and the ice
might cause quite a bit of scattering, so a parabolic dish wouldn't get
a good focus.
Chris Simmons
> The ice will move pretty slowly. The hot probe will, I think, be surrounded
> by a bubble of liquid water and vapor, which will tend to alleviate this
> problem.
>
> But getting a signal out to the surface will probably depend upon unreeling
> a cable behind the descending probe. Cables running throgh ice are often
> snapped by stresses in terrestrial Arctic experiments; designing a cable
> that can survive Europan conditions will be a challenge.
>
Surely we've got some kind of (or could make) a stretchy fibre optic cable
or something? That'd be lightweight high bandwidth and generally fab. Or
do such not exist?
Chris Simmons.
Don't bother, the web page is crap ;)
http://www.york.ac.uk/~cps102
Amw
Chris Simmons wrote:
> >
> > The ice will move pretty slowly. The hot probe will, I think, be surrounded
> > by a bubble of liquid water and vapor, which will tend to alleviate this
> > problem.
> >
> > But getting a signal out to the surface will probably depend upon unreeling
> > a cable behind the descending probe. Cables running throgh ice are often
> > snapped by stresses in terrestrial Arctic experiments; designing a cable
> > that can survive Europan conditions will be a challenge.
> >
> [snips]
> Surely we've got some kind of (or could make) a stretchy fibre optic cable
> or something? That'd be lightweight high bandwidth and generally fab. Or
> do such not exist?
Why worry about cables? Encode the data for an audio frequency and use a WQC or
underwater phone to transmit it to a listening station topside. Sound travels a
lot better underwater than radio, and the lack of a cable will give you more
mobility.
Ben
Jan Panteltje
>> the first mars probe, that was POSITIVE, would give an indication
>> of life?
>
>I'm not aware that the Viking probe included a test for amino acid
>chirality. I do recall a test in which radioactively-labeled organic
>compounds were added to the Martian soil. The test was to look for the
>appearance of the label in other compounds, which would suggest metabolic
>processes. IIRC, a positive result was obtained, but was then duplicated
>on Earth using non-living zeolite clays.
>
>The Murchison meteorite showed a modest excess of L-amino acids. Are you
>thinking of this study?
>
>Chemistry is powerful stuff, but I still want a microscope on the Europa
>Sea Explorer.
>
>> The following URL may be also of interest to you:
>> www.spie.org/web/abstracts/3100/3111.htm
>
>Your link didn't work -- I got an error message from SPIE.
>
>John J. Ladasky Jr., Ph.D.
>Department of Structural Biology
>Stanford University Medical Center
No I was indeed referring to the test for organic compounds.
Yes the link is old, probably changed.
As far as the microscope, what kind of microscope?
A powerful optical one connected to a CCD camera, with some sort of
manupilators?
Then you also need a lot of other stuff, to prepare samples.
maybe also an electron microscope?
I am all for it, but operating all that may not be so easy,
think of the time delay, that system would have to be autonomous?
Regards
Jan
Brian Davis
[several good ideas on how to cope with the silt issue; one point:]
> Since the outside of the probe will be several hundred degrees
> hotter than the ice, I expect there will be lots of convection in
> the water, enough to stir up any silt that accumulates-- as
> long as there's not much of it.
Keep in mind that convection depends on differences in bouancy, not
temperature - I'm not being picky here, I'm just pointing out that
gravity (specificly Europa's weak gravtiy) will come into the issue, as
well as the temperature/density behavior of liquid water at a
*wide* variety of pressures as the probe descends - I agree, lots of
testing on Earth is good, but there's some things you're going to have
problems testing in a lab (melting ice at 100 K at pressure up to many
kilobar, for instance, probably isn't going to be cheap).
Another possibility, for those who want a melter with no moving
parts: heat the water inside the probe body, producing very hot water
(steam?) which is ejected out of the nose, while cooler water is pulled
in the rear of the probe (possibly with no moving parts and some
plumbing, I think). Thermally-driven currents to sweep the working face
clean. I agree that eventually silt buildup will cause an issue however.
--
Brian Davis
Frank Crary
Richard Hendricks <hen...@austin.rr.com> wrote:
>I think a big wire cutting across Jupiter's magnetic field
>would cause such a drag on a probe it would be difficult to manage.
>Didn't NASA do experiments with using a ribbon of wire to drag
>satellites out of Earth orbit?
Yes, but the Earth's magnetic field just above the surface is
quite a bit stronger than Jupiter's magnetic field at the orbit
of Europa. Typical numbers are 400 nT for the magnetic field and
the orbital velocity of Europa is about 13 km/s. That gives an
induced potential of 5 V/km. (For a wire aligned perpendicular to
the velocity and magnetic field; the induced potential is zero for
a wire parallel to either the velocity of magnetic field.) That's
not a big deal, especially since communications would involve
fairly small currents. In contrast, the induced field for the TSS-1R
experiment was more like 225 V/km and they were running way more
current through it that communications would require. But, hell, if
you think this would still be a problem, then use a fiber optic
cable...
Frank Crary
lad...@my-deja.com
j...@panteltje.demon.nl (Jan Panteltje) wrote:
> As far as the microscope, what kind of microscope?
> A powerful optical one connected to a CCD camera, with some sort of
> manupilators?
> Then you also need a lot of other stuff, to prepare samples.
> maybe also an electron microscope?
> I am all for it, but operating all that may not be so easy,
> think of the time delay, that system would have to be autonomous?
Thanks for making me think this through. Given the transit time of
signals to Jupiter, the microscope on the Europa Sea Explorer would
indeed have to operate itself. And you're right, it isn't simple to
design an autonomous microscope system. But it can be done.
I was thinking of an optical microscope. I have thought of several
technologies that might be useful to include in the instrument package,
which I will list below.
1) flow cytometry;
2) microscope auto-focus capabilities;
3) cell sorting (fluid switch or optical tweezers);
4) sample concentration by micro-filtration;
5) microscope auto-collimation capabilities;
Technologies 1-4 have already been demonstrated. As far as I know,
technology #5 has not, but should not prove difficult, and perhaps is not
even necessary.
Here's what I imagine now. The front end of the sample analysis package
would be a flow cytometer. Flow cytometers were originally designed to
analyze human blood cells in liquid suspension. They have been adapted
by ocean scientists for the analysis of phytoplankton. While these are
typically laboratory instruments that require human attendance, one
research group is trying to build a self-contained plankton-monitoring
flow cytometer that would be mounted in a buoy:
http://home.wxs.nl/~dubelaar/cytobuoy.html
Such a flow cytometer would have to handle a lot of its own operations.
If this can be done, I am confident that a flow cytometer could be made
to operate remotely from a spacecraft.
I won't go into too much detail about how a flow cytometer works.
Briefly, fluid is drawn into a narrow cuvette, such that each particle in
the stream is more or less in single file. A laser beam shines through
the cuvette. Light detectors are placed to collect the narrow-angle and
90-degree angle scattered light, and optionally fluorescence. The
dimensions and the granularity of particles can be inferred from the
widths, heights, and shapes of the pulses observed at the light
detectors. This is kind of a "one-dimensional microscope." A consistent
particle size and granularity indicates a specific kind of particle. The
smallest particles that can be seen by typical flow cytometers are about
0.5 microns in diameter -- many times smaller than most cells in Earth
life.
We would probably want to look more closely at populations of particles
that were of a consistent size and granularity. Automated software has
been developed that can identify "clusters" of events. Once an
interesting population has been identified, the next step would be to
trap some of the particles, and view them with a "real" microscope.
Since the entire system would be operating underwater, I would guess that
the best way to do this would be to use a simple fluid switch, timed to
open as the desired particle comes by. This is standard technology on
several existing instruments.
The eluate from the fluid switch could be pumped into a chamber with,
say, 0.2 micron pores, in order to concentrate the sample. One side of
this chamber would be a coverslip, into which a microscope would look.
Automated systems already exist that can focus a microscope.
If the fluid system runs sufficiently slowly, it might also be possible
to trap the particle with optical tweezers. This approach would have the
added advantage that one could deliver the particle directly to the
viewing point of the microscope. But optical tweezers require a rather
powerful laser (on the order of one watt!), so it would be costly.
Over ten years ago, it was suggested that a full-blown flow cytometer and
particle sorter could be implemented as a single, solid state device that
would include diode lasers, photodiode detectors, and fluid switches.
This could be done using a hybrid of conventional semiconductor
photolithography and the new "micro-machining" technology:
http://mems.isi.edu/archives/otherWWWsites_tutorial.html
Such a system would have the advantage that the optics, once designed,
would not go out of alignment. It might also be possible to build a
complete microscope in a solid-state package.
I have no idea whether an electron microscope can be automated.
Generating a vaccuum and shadowing samples with metal would both seem to
be difficult tasks. But we learned a lot about living organisms on Earth
before we had electron microscopes. Unless every living thing that the
Europa Sea Explorer encountered was smaller than 0.5 microns in every
dimension, an electron microscope would not be needed.
--
John J. Ladasky Jr., Ph.D.
Department of Structural Biology
Stanford University Medical Center
Jan Panteltje
Since you have a Ph.D they may be willing to pay more
attention then if someone with just a year university
has an idea.
They have this programs and proposal requests, I have seen it on the
web, and even in some newsgroup (this one?), it does not hurt to
work out something, maybe it will cause a light to come on with them.
Technically there is also a pressure problem, in an ocean 60km deep,
the pressure would be horrendous.
Best chance would indeed be, as someone mentioned, to look at things at the
surface, like shells almost, or other materials left behind by living
organisms.
Almost like fossils.
Jan
Tom
Remember also that the hydraulic pressure under 60 miles of Ice on
Europa is equal to 40 percent DEEPER than the Marianas Trench. That
thing will have to withstand about 25,000 psi (188 MPa) of water
pressure. And that's at the *top* of the liquid ocean.
Matthew Montchalin
What would a 'quake' look like on Europa? Does Europa have lots of
quakes every few minutes, or does it save up its stresses for really
'WHOPPER' quakes every few years???
Since it has a pretty smooth surface, and there are lots of cracks all
over its surface, is it reasonable to conclude that the moon suffers
quakes on a pretty much continuous basis?
Matthew Montchalin
On Thu, 20 Jan 2000, Jan Panteltje wrote:
|Technically there is also a pressure problem, in an ocean 60km deep,
|the pressure would be horrendous.
But because the body is so small, would the pressure really be that
'weighty?' I'd worry more about thermal activities down there...
|Best chance would indeed be, as someone mentioned, to look at things at
|the surface, like shells almost, or other materials left behind by
|living organisms.
|Almost like fossils.
Yes!
But at least we are all agreed on the need for an orbital surveyor, and
some seismometer-bots laid on its surface. Rovers could come after that.
Matthew Montchalin
|>|Technically there is also a pressure problem, in an ocean 60km deep,
|>|the pressure would be horrendous.
|>
|>But because the body is so small, would the pressure really be that
|>'weighty?' I'd worry more about thermal activities down there...
|
| Yes, it would be that "weighty". Pressure at depth can be found with
|the follwing equation:
| P = P(0) + ( rho * g * h ) , WHERE
|P(0) is the pressure of the atmosphere above the water
|rho is the density of the water (which I'll assume to be pure, even though
How are you arriving at the water 'density?' Are you referring to the
'specific gravity' of water, as opposed to the 'specific gravity' of any
other fluid?
For instance, at the surface (as you already pointed out), density must
be negligible because 'water ice' boils in a vacuum.
Matthew Montchalin
|*some* pressure to keep a liquid ocean liquid. This assumption and the
|fresh water assumption give a pressure at depth smaller than it would
|*really* be at the bottom of a 60-km ocean.
|
|So P = 0 + ((1 g/cm^3)*(144 cm/s^2)*(6000000 cm))
Why do you believe that water density at any given distance from the
crust of Europa is 1 gram per cubic centimeter?
Forgive me, but I need to understand this every step of the way.
lad...@my-deja.com
Tom <t2...@bellsouth.net> wrote:
> Europa is equal to 40 percent DEEPER than the Marianas Trench. That
> thing will have to withstand about 25,000 psi (188 MPa) of water
> pressure. And that's at the *top* of the liquid ocean.
Hmmm. This seems like all the more reason to microfabricate a solid-
state analysis package. With no air in the system at all, pressures will
be equalized.
What sorts of instruments have been placed on terrestrial deep-sea
probes? How are they designed? Surely there must be some experience
with this.
Matthew F Funke
>|the pressure would be horrendous.
>
>'weighty?' I'd worry more about thermal activities down there...
Yes, it would be that "weighty". Pressure at depth can be found with
the follwing equation:
P = P(0) + ( rho * g * h ) , WHERE
P(0) is the pressure of the atmosphere above the water
rho is the density of the water (which I'll assume to be pure, even though
salt water is denser, and Europa's ocean is likely salt water
g is the acceleration due to gravity, roughly 1.44 m/s^2 on Europa
h is the depth of the ocean
Let's assume that P(0) is negligible, although there would have to be
*some* pressure to keep a liquid ocean liquid. This assumption and the
fresh water assumption give a pressure at depth smaller than it would
*really* be at the bottom of a 60-km ocean.
So P = 0 + ((1 g/cm^3)*(144 cm/s^2)*(6000000 cm))
= 864 million dynes per square cm
= 853 times the pressure of Earth's atmosphere (!)
The amount of force on that probe would be equivalent to
concentrating the weight of a small car in Earth's gravity field on
*every* *square* *centimeter*. THAT's weighty. (I assumed that a small
car has a weight of 880 kg, just under an English ton.)
--
-- Lurking in the Shadows,
"Nikolai" (m...@hopper.unh.edu)
Goth.Code 4.0 zUibba3baWabaaaaLbaa75KxARUSvacnmeiybZan3FmaH17T1aGbZueaqiq
5eedO#di1hbjrpk6!RpsEbacRZUFaaaicaeusnh
Matthew Montchalin
|So P = 0 + ((1 g/cm^3)*(144 cm/s^2)*(6000000 cm))
| = 864 million dynes per square cm
| = 853 times the pressure of Earth's atmosphere (!)
|
| The amount of force on that probe would be equivalent to
|concentrating the weight of a small car in Earth's gravity field on
|*every* *square* *centimeter*. THAT's weighty. (I assumed that a small
|car has a weight of 880 kg, just under an English ton.)
Assuming that the formula is correct, and I have no reason to say it
isn't, you are quite right, that is a lot of pressure. How does it
compare to the lowest point of any given ocean on Earth?
Matthew F Funke
>crust of Europa is 1 gram per cubic centimeter?
I've been told that water can be treated as an essentially
incompressible fluid with a density -- or "specific gravity", if you
prefer -- of 1 gram per cubic centimeter. Technically, it's only at that
density at 4 degrees Celsius and 1 atmosphere pressure, but I've also been
told that under all other circumstances that 1 is "close enough".
If there are extenuating circumstances that need to be considered
here, I'm not aware of them.
It is interesting to note that it's been pointed out that P(0) is
already 40% greater than the pressure at the bottom of the Earth's deepest
oceanic location (the Marianis Trench), so that pressure needs to be added
to the figure I already came up with to represent the *true* pressure.
>Forgive me, but I need to understand this every step of the way.
Not at all. If there's something I'm missing or getting wrong, it
could be a great opportunity for me to learn, too. I appreciate being
held to my claims.
Matthew F Funke
>
>'specific gravity' of water, as opposed to the 'specific gravity' of any
>other fluid?
Technically, yes. But this was supposed to be a non-technical, rough
calculation, so referring to water's specific gravity loosely as
"density" seemed okay to me.
>For instance, at the surface (as you already pointed out), density must
>be negligible because 'water ice' boils in a vacuum.
Yes. It has also been pointed out that, because of the pressure of
the surface layer of ice, the pressure at the top of the ocean on Europa
is already some 40% greater than the pressure at the bottom of the
Marianis Trench (some 6.5 miles below sea level at the bottom of the
Pacific, if memory serves). So at the surface of Europa's ocean, the
pressure is *not* negligible.
Matthew F Funke
The lowest point in Earth's oceans is the Marianis Trench, which (if
I recall correctly) is about 6.5 miles below sea level, or about 10.5 km.
(I'm not paying real strict attention to significant figures, which I
should be, really -- but this is just a fast and loose calculation with my
pocket calculator.)
The pressure at sea level from the atmosphere is 1013250 dynes per
square centimeter. That's P(0).
g at Earth's surface is 981 cm/s^2.
Unfortunately, since I don't know the density of sea water, I'm going
to have to assume again that the water is pure, and that rho = 1 g/cc. In
reality, it would be more than this, making the end pressure higher.
Plug that into the formula I had earlier:
P = P(0) + (rho * g * h)
= 1013250 dynes/cm^2 + ((1 g/cc) * (981 cm/s^2) * (1050000 cm))
= 1031000000 dynes/cm^2
= 1020 atmospheres (!)
As someone has pointed out, though, the ice covering Europa's ocean
creates a not insubstantial pressure on the surface, so P(0) (which I
ignored previously) is not a term that can be ignored.
Assuming that the figure provided is correct (40% greater than the
pressure at the Marianis Trench at the *top* of Europa's ocean) and that
my calculation of the Marianis Trench's pressure was based on an accurate
depth, the pressure at the bottom of Europa's ocean becomes
P = (1020 atmospheres)(1.4) + 853 atmospheres
= 2280 times the pressure of Earth's atmosphere at the bottom of
Europa's ocean (!)
That's more than the weight of two and a half of the small cars I
used earlier pressing down on *every* *square* *centimeter* of probe.
Squish.
Of course, if you want a *real* challenge, this is *nothing* compared
to the pressures created in the depths of Jupiter's atmosphere...
Hiram Berry
Matthew F Funke <m...@hypatia.unh.edu> wrote in message
news:869tpe$u51$1...@tabloid.unh.edu...
> As someone has pointed out, though, the ice covering Europa's ocean
> creates a not insubstantial pressure on the surface, so P(0) (which I
> ignored previously) is not a term that can be ignored.
The interface between the ice crust and the subsurface ocean ought to occur
at a point where the internal time-averaged heat production (due to tidal
flexing+eddy currents from the conductive ocean moving through Jupiter's
magnetic field?) balances thermal conduction outward through the crust. If
that actually occurs at a depth of 100 km, it's really interesting. Look at
a phase diagram for water/ice.
> Assuming that the figure provided is correct (40% greater than the
> pressure at the Marianis Trench at the *top* of Europa's ocean) and that
> my calculation of the Marianis Trench's pressure was based on an accurate
> depth, the pressure at the bottom of Europa's ocean becomes
Okay, but I think it might be even a little more than that, due to the facts
that saline solutions (or sulfuric acid solutions, which would be the other
reasonable possibility in my mind) are denser than pure water, and at these
pressures water itself has significant compressibility. Of course there is
the countervailing effect that g is reduced somewhat as you go deeper.
An interesting thing to me is that the crust/ocean interface would occur
just a little bit (on the phase diagram) off of the triple point of liquid
H20/ice I/ice III at around -25C and around 1.8kbars (if I'm reading the
diagram closely enough). Now if you assume that the temperature of the
ocean is uniform, that it stays roughly the same as the pressure increases,
a strange thing happens; the pressure doesn't have to increase much before
the water solidifies again... into a completely different crystalline form
of ice, ice V! And the depth of your ocean could be determined simply by
the position of the H2O(l)/ice V curve.
That makes a very delicate and sensitive system-- increase the thickness of
the crust just a little and the ocean couldn't exist. Vary the energy flux
over time and the phase boundaries could advance and retreat by kilometers--
and between phases which have significantly different densities. Strong
shocks would result as metastable regions suddenly changed state.
_________________
Hiram Berry
Matthew Montchalin
|Matthew F Funke <m...@hypatia.unh.edu> wrote in message
|news:869tpe$u51$1...@tabloid.unh.edu...
|> As someone has pointed out, though, the ice covering Europa's
|> ocean creates a not insubstantial pressure on the surface, so P(0)
|> (which I ignored previously) is not a term that can be ignored.
|
|The interface between the ice crust and the subsurface ocean ought to
|occur at a point where the internal time-averaged heat production (due
|to tidal flexing+eddy currents from the conductive ocean moving through
|Jupiter's magnetic field?) balances thermal conduction outward through
|the crust.
Okay, that makes sense.
|If that actually occurs at a depth of 100 km, it's really interesting.
|Look at a phase diagram for water/ice.
I don't have a phase diagram handy.
How sharp would the interface zone(s) be? If ice has several kinds of
phase, depending on pressure, would it be reasonable to conclude that
different depths have different 'kinds' of ice? And between each of
these ice types, there would be amorphous, shifting or shiftable, high
pressure 'slushes?'
Matthew Montchalin
On 21 Jan 2000, Hiram Berry wrote:
|occur just a little bit (on the phase diagram) off of the triple point
|of liquid H20/ice I/ice III at around -25C and around 1.8kbars (if I'm
|reading the diagram closely enough). Now if you assume that the
|temperature of the ocean is uniform, that it stays roughly the same as
|the pressure increases, a strange thing happens; the pressure doesn't
|have to increase much before the water solidifies again... into a
|completely different crystalline form of ice, ice V! And the depth of
|your ocean could be determined simply by the position of the H2O(l)/ice
|V curve.
Amazing... But all of that depends on reasonably pure H20? What are the
phases for 'dirty' water?
|That makes a very delicate and sensitive system-- increase the thickness
|of the crust just a little and the ocean couldn't exist. Vary the energy
|flux over time and the phase boundaries could advance and retreat by
|kilometers-- and between phases which have significantly different
|densities. Strong shocks would result as metastable regions suddenly
|changed state.
Would the shocks be stronger the dirtier the water is? If the water is
liquid, and then freezes because of a change in pressure, one way or the
other, would this serve to isolate impurities from the water or ice?
If water regularly melts and refreezes, changing state as pressure
changes, would impurities tend to clump and fall down, away from the
surface?
Matthew Montchalin
On Fri, 21 Jan 2000, Matthew Montchalin wrote:
|If water regularly melts and refreezes, changing state as pressure
|changes, would impurities tend to clump and fall down, away from
|the surface?
If that is the case, it makes it less probable that extrusions
(I mean, in the nature of rising ice plumes) would bear 'hard
fossilized remains' of life forms otherwise deep inside Europa.
If salts and impurities tend to clump and "fall down" or sink
as water repeatedly melts and refreezes, then we should expect
to see reasonably 'pure' ices on the crust of Europa.
inova
but I read that los alamos labs have such a device
Bill Higgins-- Beam Jockey wrote:
> On 13 Jan 2000 SEN...@argo.rhein-neckar.de wrote:
> > Such a type of Europa probe was discussed here in alt/sci/planetary
> > or sci/space/tech about a year ago up to some detail. In the later
> > even 5 years ago before Dejanews!
>
> Wow, I didn't expect my five-year-old postings to be quoted here!
>
> >>Absender : hig...@fnalv.fnal.gov (Bill Higgins-- Beam Jockey)
> >>Betreff : Melt-Mobile (was Re: Probing Europa's Oceans (was Re: Europa...))
> >>Datum : Do 16.03.95, 13:30 (erhalten: 19.03.95)
> >>----------------------------------------------------------------------
> >>In article <lpurpleD...@netcom.com>, lpu...@netcom.com (Lance Purple) *
> >>> Brian Yamauchi <yama...@ces.cwru.edu> asks:
> >>>>
> >>>>Suppose you landed a nuclear reactor (a Topaz, for example) on
> >>>>Europa's surface . . . then triggered a meltdown.
> >>
> >>[Lance's clever RTG-based design ideas omitted]
> >>
> >>Nobody has pointed out that in the early Sixties, somebody proposed
> >>building a probe like this for exploring the Earth's crust. Build a
> >>tall torpedo-shaped vehicle out of materials which can resist extremely
> >>high temperatures (I don't know, over 1000 K? 2000 K?) Start up the
> >>nuclear reactor within it and it will begin to melt the rock it's
> >>parked on. It descends to a predetermined depth, or maybe waits for a
> >>predetermined time, somehow trapping magma samples along the way.
> >>Then it drops its lower end, which is dense ballast, and melts its way
> >>back up to the surface.
> >>
> >>The ultimate "not in MY back yard!" toy.
> >>
> >>No references handy, but it was mentioned in the "Science" section of
> >>*Time* when I was in grade school, so it's possible to track down.
>
> I have since done some research on this. William Manchester Adams, a
> geophysicist at Lawrence Livermore National Laboratory, in 1961 patented a
> gadget like this. I don't know where he is now, but he was working at
> Western Washington Univeristy in 1990.
>
> > It has similarities to this proposed "Earth Diver" by Edward Teller.
>
> Teller ran Livermore around that time; perhaps he knew Adams and his scheme?
>
> --
> ___ O~~* /_) ' / / /_/ ' , , ' ,_ _ \|/
> / / - ~ -~~~~~~~~/_) / / / / / / (_) (_) / / / _\~~~~~~~~~~~zap!
> /__// \ (_) (_) / | \
> | | Bill Higgins Fermi National Accelerator Laboratory
> \ / Bitnet: Sic transit gloria mundi
> - - Internet: HIG...@FNAL.FNAL.GOV
> ~ SPAN/Hepnet/Physnet: 43011::HIGGINS
Patrick & Sangeeta Bishop
the hole, than about sending telemetry back. I'm sure there are frequencies of
radio waves to which the Europan crust would be perfectly transparent.
That being the case, why not find out what those frequencies are and use them in a
radar array to scan Europa's guts?
Cheers,
Patrick