Interstellar Propulsion idea using an Asteroid and a few comets!
Abdul Ahad
the thing a while back, but have not had much time to take it forward
to completion:-
http://uk.geocities.com/aa_spaceagent/restricted/interstellar-propulsion.html
Has anyone come across an Asteroid-Comet amalgam for a space ship
design like mine? If I am re-inventing the wheel with my
*revolutionary* "Ahad-AstroCom" generation starship concept... then
please tell me!
I will proceed with the idea, but its gonna take many hours at the PC!
cheers,
Abdul Ahad
-----------------------------------------------------------------------------
http://uk.geocities.com/aa_spaceagent/
"We have lingered long enough on the shores of the cosmic ocean. We
are ready at last to set sail for the stars"........Carl Sagan
-----------------------------------------------------------------------------
Androcles
"Abdul Ahad" <aa_spa...@yahoo.co.uk> wrote in message
news:3416b228.0408...@posting.google.com...
energy required will be astronomical, and energy = money. Who is paying and
what is the payback expected?
Androcles.
Graham W
> the thing a while back, but have not had much time to take it forward
> to completion:-
>
>
http://uk.geocities.com/aa_spaceagent/restricted/interstellar-propulsion.h
tml
>
> Has anyone come across an Asteroid-Comet amalgam for a space ship
> design like mine? If I am re-inventing the wheel with my
> *revolutionary* "Ahad-AstroCom" generation starship concept... then
> please tell me!
>
> I will proceed with the idea, but its gonna take many hours at the PC!
Isn't Space Ship design *off-topic* for uk.sci.astronomy ?
--
Graham W http://www.gcw.org.uk/ PGM-FI page updated, Graphics Tutorial
WIMBORNE http://www.wessex-astro-society.freeserve.co.uk/ Wessex
Dorset UK Astro Society's Web pages, Info, Meeting Dates, Sites & Maps
Change 'news' to 'sewn' in my Reply address to avoid my spam filter.
Eric Gisse
wrote:
>I wonder if this idea is worth pursuing to further detail. I started
>the thing a while back, but have not had much time to take it forward
>to completion:-
>
>http://uk.geocities.com/aa_spaceagent/restricted/interstellar-propulsion.html
Won't work.
Not only do you have no reason to believe that there is a nice trail
of comets leading to the Centauri system, you totally ignore time of
flight and how to keep people alive during the many centuries of
travel.
>
>Has anyone come across an Asteroid-Comet amalgam for a space ship
>design like mine? If I am re-inventing the wheel with my
>*revolutionary* "Ahad-AstroCom" generation starship concept... then
>please tell me!
Generation ships.
>
>I will proceed with the idea, but its gonna take many hours at the PC!
Direct your efforts towards something more productive, such as getting
some national government which has space capabilities to use an Orion
drive system.
AA Institute
> On 13 Aug 2004 09:06:26 -0700, aa_spa...@yahoo.co.uk (Abdul Ahad)
> wrote:
>
> >I wonder if this idea is worth pursuing to further detail. I started
> >the thing a while back, but have not had much time to take it forward
> >to completion:-
> >
> >http://uk.geocities.com/aa_spaceagent/restricted/interstellar-propulsion.html
>
> Won't work.
>
> Not only do you have no reason to believe that there is a nice trail
> of comets leading to the Centauri system,
It is very much dependent on how sparsely spaced icy objects such as
comets are distributed for a few light years beyond our solar system.
I agree "it is the vision of an optimist!" as I emphasise near the
begining, and bordering on sci-fi as far as our current technology and
costs are concerned!
*If* on the other hand, based on future, more advanced telescopic
observations it transpires that there is a lot more debris out there
than we previously thought, then there may be some merit to this
concept. If the recent discovery of Sedna at a distance of... was it
something like 3 x the Sun-Pluto distance, is any guide to go by then
icy objects may be scattered in much more abundance and further out
than we previously thought.
> you totally ignore time of
> flight and how to keep people alive during the many centuries of
> travel.
The gaseous and water/methane-ice resources from comets captured along
the journey will be sucked into the asteroid via anchored pipe lines,
processed and refined to feed through to fuel for spacecraft
propulsion and the surplus used to provide heating and lighting for
the asteroid colony (the people, plants and animals living as one self
sustaining 'biosphere' inside the rock).
>
> >
> >Has anyone come across an Asteroid-Comet amalgam for a space ship
> >design like mine? If I am re-inventing the wheel with my
> >*revolutionary* "Ahad-AstroCom" generation starship concept... then
> >please tell me!
>
> Generation ships.
Generally, yes I agree. Is there a *specific* design out there though,
which is based on continuous "comet sucking" for propulsion and crew
life support that you may be aware of?
>
> >
> >I will proceed with the idea, but its gonna take many hours at the PC!
>
> Direct your efforts towards something more productive, such as getting
> some national government which has space capabilities to use an Orion
> drive system.
Are there any internet links to the Orion drive system, it sounds very
interesting?
Eric Gisse
wrote:
>Eric Gisse <fseggNO!SP...@uaf.edu> wrote in message news:<go8qh0tp77c4jtufv...@4ax.com>...
>> On 13 Aug 2004 09:06:26 -0700, aa_spa...@yahoo.co.uk (Abdul Ahad)
>> wrote:
>>
>> >I wonder if this idea is worth pursuing to further detail. I started
>> >the thing a while back, but have not had much time to take it forward
>> >to completion:-
>> >
>> >http://uk.geocities.com/aa_spaceagent/restricted/interstellar-propulsion.html
>>
>> Won't work.
>>
>> Not only do you have no reason to believe that there is a nice trail
>> of comets leading to the Centauri system,
>
>It is very much dependent on how sparsely spaced icy objects such as
>comets are distributed for a few light years beyond our solar system.
>I agree "it is the vision of an optimist!" as I emphasise near the
>begining, and bordering on sci-fi as far as our current technology and
>costs are concerned!
No.
Your optimism is founed upon ignorance.
There is no reason to believe there is any signifigant distribution of
comets/asteroids past the heiopause. The heliopause is the point where
Sol's stellar wind is indistinguishable from the rest of the crap
being sent out from other stars.
>
>*If* on the other hand, based on future, more advanced telescopic
>observations it transpires that there is a lot more debris out there
>than we previously thought, then there may be some merit to this
>concept. If the recent discovery of Sedna at a distance of... was it
>something like 3 x the Sun-Pluto distance, is any guide to go by then
>icy objects may be scattered in much more abundance and further out
>than we previously thought.
You lack a sense of scale.
Light from Sol to Earth takes 8 minutes.
Light from any of the stars in the Centauri system takes anywhere from
4 to 4.5 years to get here.
Light speed is roughly 3 x 10^8 meters per second. The only drive
system, that is even remotely feasable, which could take us to a star
in less than a few thousand years would be Orion or some kind of
hybrid nuclear / ion drive.
>
>> you totally ignore time of
>> flight and how to keep people alive during the many centuries of
>> travel.
>
>The gaseous and water/methane-ice resources from comets captured along
>the journey will be sucked into the asteroid via anchored pipe lines,
>processed and refined to feed through to fuel for spacecraft
>propulsion and the surplus used to provide heating and lighting for
>the asteroid colony (the people, plants and animals living as one self
>sustaining 'biosphere' inside the rock).
...you know this how? You are yet to give a figure for the
acceleration of the ship or time of flight.
>
>>
>> >
>> >Has anyone come across an Asteroid-Comet amalgam for a space ship
>> >design like mine? If I am re-inventing the wheel with my
>> >*revolutionary* "Ahad-AstroCom" generation starship concept... then
>> >please tell me!
>>
>> Generation ships.
>
>Generally, yes I agree. Is there a *specific* design out there though,
>which is based on continuous "comet sucking" for propulsion and crew
>life support that you may be aware of?
Not that I am aware of. I would doubt it, considering there is no
reason to believe there is enough stuff out there to use that is
larger than a hydrogen atom.
>
>>
>> >
>> >I will proceed with the idea, but its gonna take many hours at the PC!
>>
>> Direct your efforts towards something more productive, such as getting
>> some national government which has space capabilities to use an Orion
>> drive system.
>
>Are there any internet links to the Orion drive system, it sounds very
>interesting?
It is. Pulsed nuclear weapon blasts pushing a spaceship. Do not use in
planetary atmospheres. It will never see the light of day in America.
Ask the Russians nicely, or setup a disposable launch platform out in
the Pacific if you don't care about making a mess.
http://www.islandone.org/Propulsion/ProjectOrion.html
[snip]
Alfred A. Aburto Jr.
Yes, there is reason. The Oort Cloud of comets go well beyond the
heliopause.
The Oort Cloud of comets may extend out to 100,000 AU --- maybe 3 light
years from the Sun. This is a good fraction of the way to the nearest star.
Abdul Ahad's idea is a good one I think. Take advantage of the Oort Cloud
of comets for resources to try to make it to the nearest star. Well, I'm
sure
Alpha Centauri A/B and Proxima Centauri at ~4.3 light years away from the
Sun have their own similar Oort Cloud of comets so one could probably
make it all the way from Earth to the Alpha Centauri system taking advantage
of comets (the comets would certainly have all sorts of organic compounds
and chemicals and water!!).
For the Oort Cloud of comets see for example:
http://zebu.uoregon.edu/~js/glossary/oort_cloud.html
Great idea! ...
Al
Robi
> Eric Gisse wrote:
>> Abdul Ahad wrote:
>>>I wonder if this idea is worth pursuing to further detail. I started
>>>the thing a while back, but have not had much time to take it forward
>>>to completion:-
>>>
>>>http://uk.geocities.com/aa_spaceagent/restricted/interstellar-propulsion.html
>>
>> Won't work.
>>
>> Not only do you have no reason to believe that there is a nice trail
>> of comets leading to the Centauri system,
>
> It is very much dependent on how sparsely spaced icy objects such as
> comets are distributed for a few light years beyond our solar system.
> I agree "it is the vision of an optimist!" as I emphasise near the
> begining, and bordering on sci-fi as far as our current technology and
> costs are concerned!
>
> *If* on the other hand, based on future, more advanced telescopic
> observations it transpires that there is a lot more debris out there
> than we previously thought, then there may be some merit to this
> concept. If the recent discovery of Sedna at a distance of... was it
> something like 3 x the Sun-Pluto distance, is any guide to go by then
> icy objects may be scattered in much more abundance and further out
> than we previously thought.
Abdul, iy would be 'nearly' impossible with our current technology to
a) catch a comet and adjust its trajectory and speed or
b) grab an asteroid large enough and match the comet's speed and trajectory
for such an enterprise.
if we had that technology we wouldn't even need to think about this solution :)
star trek fans know about tachyon particles, but it's not only them:
<http://www.bioenergyresearch.com/eng/takionic_energy.htm>
<quote>
Tachyon energy:
With the term "tachion" physics identifies a particle held to be theoretic,
capable of traveling at a speed faster than light.
At the end of the nineteenth century Nikola Tesla noted during an eclipse of
the sun certain anti-gravitational phenomena: delving further into this he
discovered an energy field which he patented under the name "cosmic energy",
in that all the universe is immersed in it.
In the course of the XX century numerous scientists have further developed
their research into this field of energy: "Feinberg's Field" or "Tachyonical",
so called by the physicist Feinberg who set forth one of his theories in 1966.
Space is not empty, but immersed in a very concentrated energy field, composed
of these theoretic particles which move faster than light and which constitutes
a source of free energy, situated outside the electromagnetic field,
independently of light and of the sun.
It is a primary energy which creates and maintains order in the chaos of matter.
When the flux of this energy is shrunk, the organism does not regenerate and
disturbances are born and the body deteriorates.
From this is born the need to keep ourselves open to this flux of tachyonic
energy.
Tachyonic energy therefore permeates all of creation and all human beings who
dwell within it, enabling biological systems to regenerate themselves through
the innate ability that they possess to assimilate this vital energy.
The tachyonic field, in essence, constitutes an inexhaustible font of energy
which can be used for the benefit of living beings.
[from here on it talks about their product]
</quote>
the ability to use such an energy would probably solve starflight in the
areas of speed and ship-hull strength.
tachyon energy could be "refueled" on the way.
--
Robi
for SETI: 3.6#@ 3.37
Alfred A. Aburto Jr.
>"Robi" <m...@privacy.net> wrote in message
news:2o6nueF...@uni-berlin.de...
We can catch a comet of course ... there are several comet projects going on
now (Wild & Deep Impact).
Using a comet or asteriod as a vehicle is of course a big problem. But you
don't have to use a comet as a space ship.
We could build for example a "space ship" out near the orbit of Pluto or
near to the Kuiper Belt of comets and go from there crossing the space
between the Sun and the Alpha Centauri system by using the resources offered
by the comets along the way. Comets should have all kinds of resources
including water and organic compounds from which fuel could be made ...
The neat idea here is to take advantage of the resources of comets from here
to the Alpha Centauri system ...
Al
Ian Stirling
<snip>
> Yes, there is reason. The Oort Cloud of comets go well beyond the
> heliopause.
> The Oort Cloud of comets may extend out to 100,000 AU --- maybe 3 light
> years from the Sun. This is a good fraction of the way to the nearest star.
Assuming this is correct.
It doesn't give you any benefit.
How are you going to find dark bodies at such great distances?
How are you going to slow down and extract resources from one even if
you find it?
Alfred A. Aburto Jr.
>"Ian Stirling" <ro...@mauve.demon.co.uk> wrote in message
news:411e4269$0$7250$ed26...@ptn-nntp-reader03.plus.net...
> In sci.space.policy Alfred A. Aburto Jr. <abu...@sbcglobal.net> wrote:
> <snip>
> > Yes, there is reason. The Oort Cloud of comets go well beyond the
> > heliopause.
> > The Oort Cloud of comets may extend out to 100,000 AU --- maybe 3 light
> > years from the Sun. This is a good fraction of the way to the nearest
star.
>
> Assuming this is correct.
http://zebu.uoregon.edu/~js/glossary/oort_cloud.html
> It doesn't give you any benefit.
> How are you going to find dark bodies at such great distances?
You, of course, do not do this without being prepared, without planning ...
I'd expect one of the first goals would be to do a surveillance of the
Kepler belt comets and even (perhaps later) the Oort Cloud comets. The
surveillance could be done using powerful radars (such as Arecibo, which is
already imaging asteriods). The goal would be to determine the orbits of
comets (by the way we already know the orbits of quite a few comets that
have entered the inner Solar System). Once a sufficient data base of Kepler
belt and Oort Cloud comets was established (which may take decades or
centuries) then generate a plan to "comet hop" to the Alpha Centauri system.
> How are you going to slow down and extract resources from one even if
> you find it?
The star ship (something like the current international space station I
imagine) would have smaller and faster spacecraft used to visit the comets.
These faster, smaller, spacecraft could do the job ---- (similar to our
current spacecraft visting comet Wild and to the Deep Impact comet mission).
I see no trouble getting to the comets once we know their orbits and have a
specific plan for "comet hopping" in place. The "space station" would be "in
there" amongst the comets so to speak so I don't expect huge,
unsurmountable, velocity differences ...
Al
red
I do not doubt that some such ship could be built locally, *around* one
comet, equipped with a nuclear reactor (or some other long-term power
source), and sent to the stars. Solar sails and/or a slingshot trajectory
near our Sun may also provide cheap boosts in velocity. In-flight
re-fueling in the depths of space, however, seems very unlikely. Even IF
such stray comets do exist, drifting in space, it would cost *most* of the
energy expended thus far, to match course and velocity with these objects,
before they could be reeled in. It may even be necessary to reverse course
for that, since anything closer to us, than to the destination, would
probably be heading roughly -toward- our Solar System. So if you
accelerate for four years, are you then willing to decelerate for five
years, on the chance that the intended target body is actually a useable
comet, and not a useless rock?
I question the morality of generational starships, anyway. I might love
to explore the cosmos, but if you have ever raised children, then you know
that there is a fair chance that they will not share your dreams. Without
the radiation shielding that is the Earth and it's
atmosphere/magnetosphere, you may be consigning any generational starship
crew to increasing frequencies of birth defects, the ravages of
little-known dietary deficiencies, or diseases that become resistant to all
antibiotics on board.
At the present rate of scientific progress, I would not doubt that the
first generational ships would be passed up in flight by commercial tourist
starliners, heading out at speeds un-attainable by our best present
technology.
Those ideas combine to make a generational ship both morally irresponsible
to the crew, and scientifically useless.
The idea does hold some promise as unmanned probes, especially in the
"fly-by" stellar exploration mode proposed by Arthur C. Clarke in
"Rendezvous with Rama", and used (on an interplanetary scale) by both of
USA-NASA's Voyager space probes in our own Solar System.
The risk then would be that a true star-travelling civilization may exist,
and may find our probe, and track it back to us. As one planet "against" a
stellar empire (at any level of conquest or assimilation), we would be
*lucky* to survive with our human identity intact. I cite the experience
of Japan, in the last century. That culture now more closely resembles the
"West", than the beautiful "Far-East" that it once was; they may have lost
more than they gained, by such contact between dis-similar cultures.
--
Cheers,
Red
--
*************************
Replies will bounce, unless you remove
the letter A from my email address.
Alfred A. Aburto Jr.
>"Ian Stirling" <ro...@mauve.demon.co.uk> wrote in message
news:411e4269$0$7250$ed26...@ptn-nntp-reader03.plus.net...
By the way, using radar to find range and bearing (and thus orbit) of these
Kuiper belt and Oort Cloud comets (I think I said Kepler previously, sorry!)
would have SETI (transmit) implications of course --- there we'd be blasting
away at high power to the rest of the Galaxy!
Also, don't rule out optical telescopes. Even Hubble has had success finding
Kuiper belt comets:
http://hubblesite.org/newscenter/newsdesk/archive/releases/1995/26/
An outpost on Pluto would probably work well for optical and radio
telescopes to start us off with enough information on comets and planetiods
to start our first interstellar mission using the resources available from
these objects inhabiting the space between nearby stars ...
Al
AA Institute
> Abdul Ahad,
> I do not doubt that some such ship could be built locally, *around* one
> comet, equipped with a nuclear reactor (or some other long-term power
> source), and sent to the stars. Solar sails and/or a slingshot trajectory
> near our Sun may also provide cheap boosts in velocity. In-flight
> re-fueling in the depths of space, however, seems very unlikely. Even IF
> such stray comets do exist, drifting in space, it would cost *most* of the
> energy expended thus far, to match course and velocity with these objects,
> before they could be reeled in. It may even be necessary to reverse course
> for that, since anything closer to us, than to the destination, would
> probably be heading roughly -toward- our Solar System.
You can adjust your speed and course in advance and if necessary use a
space harpoon to catch the beast! Besides, like I said this idea of
mine is still highly *flexible* and very much a work in progress.
> accelerate for four years, are you then willing to decelerate for five
> years, on the chance that the intended target body is actually a useable
> comet, and not a useless rock?
You can do long range spectroscopic and advanced radar studies and
choose your target comets/interstellar rocks based on the suitability
of their composition for the starship needs.
> I question the morality of generational starships, anyway. I might love
> to explore the cosmos, but if you have ever raised children, then you know
> that there is a fair chance that they will not share your dreams.
I think most people would share these same concerns. The way I see
long duration interstellar travel on generation starships (like the
one I envision here) is as a kind of last resort, 'emergency' and
'flight to safety' measure for the human race at large. Its never
going to be a totally risk free option whatever method of travel you
choose. Distances to the nearest stars will stay beyond comfortable
reach with all propulsion methods and technologies within reach of our
current science.
If no part of human society ever manages to leave the cradle of our
solar system and we face extinction here where we were born, then
that's bound to be regarded as a deep tragedy from a universal
perspective. Those of us who believe the scientific processes of our
evolution, we crawled out of the oceans as tiny amphibians... swung on
trees... developed consciousness and intelligence...looked at billions
of worlds out in the cosmos through our telescopes... only to face
extinction in the end knowing we had every chance to throw our seeds
further out to safety. And why? Because we did not want to send our
sons and daughters out on a daring voyage into the risky environment
of interstellar space... Doesn't sound right to me. We send our brave
soldiers to battle fields every year knowing there is every chance
they might not make it back.
> the radiation shielding that is the Earth and it's
> atmosphere/magnetosphere, you may be consigning any generational starship
> crew to increasing frequencies of birth defects, the ravages of
> little-known dietary deficiencies, or diseases that become resistant to all
> antibiotics on board.
We will need more manned mission experience for many more decades on
places like the Moon and Mars to get to grips with these kinds of
potential hazards. Only after these have been thoroughly evaluated, we
will be ready to launch starships like mine towards Alpha Centauri.
There are vast numbers of interim hurdles to overcome and experiences
to be gained and, no, I do not believe in suicide but I do believe in
one way trips to far off lands... or worlds for that matter!
AA Institute
That's a matter of opinion and based on how flexible people want to be
about the realm of possibilities. I like to think that my concept is
not based on *complete* sci-fi, unlke many other ideas floating around
out there inside people's heads.
>
> There is no reason to believe there is any signifigant distribution of
> comets/asteroids past the heiopause. The heliopause is the point where
> Sol's stellar wind is indistinguishable from the rest of the crap
> being sent out from other stars.
But the fact remains very clear that comets do come our way in from
*interstellar* space, and quite frequently so. I am confident that
once our ability to peer deeper into space with more sensitive
instruments, we will be able to identify comets long before they reach
the heliopause. A future on-orbit multiple telescope interferometry
arrangement, like the ones planned for detecting Earth sized planets
around nearby stars, could locate faint comets perhaps as far as
several hundreds of AUs out beyond the orbit of Pluto.
>
>
> You lack a sense of scale.
>
> Light from Sol to Earth takes 8 minutes.
>
> Light from any of the stars in the Centauri system takes anywhere from
> 4 to 4.5 years to get here.
>
> Light speed is roughly 3 x 10^8 meters per second. The only drive
> system, that is even remotely feasable, which could take us to a star
> in less than a few thousand years would be Orion or some kind of
> hybrid nuclear / ion drive.
>
I have not fully detailed the propulsion methods as yet. There is
nothing to suggest that some kind of hybrid/nuclear propulsion would
not be used to augment the initial departure burn from near Earth or
in-solar system space.
> >> >Has anyone come across an Asteroid-Comet amalgam for a space ship
> >> >design like mine? If I am re-inventing the wheel with my
> >> >*revolutionary* "Ahad-AstroCom" generation starship concept... then
> >> >please tell me!
> >>
> >> Generation ships.
> >
> >Generally, yes I agree. Is there a *specific* design out there though,
> >which is based on continuous "comet sucking" for propulsion and crew
> >life support that you may be aware of?
>
> Not that I am aware of. I would doubt it, considering there is no
> reason to believe there is enough stuff out there to use that is
> larger than a hydrogen atom.
>
Good! Then my idea is a first "comet sucking", Ahad AsterCom starship
design. The countdown has already started...its ticking away silently
toward some as yet un-determined launch date which *may* come to
fruition one day...not that I'd be there to see it of course!
Alan Anderson
> ...A future on-orbit multiple telescope interferometry
> arrangement, like the ones planned for detecting Earth sized planets
> around nearby stars, could locate faint comets perhaps as far as
> several hundreds of AUs out beyond the orbit of Pluto.
Interferometry is not the appropriate tool if you're looking for faint
objects. You need a large light-collecting area, and high angular
resolution is not a substitute for that.
st...@tropheus.demon.co.uk
wrote:
>
>http://uk.geocities.com/aa_spaceagent/restricted/interstellar-propulsion.html
>
>Has anyone come across an Asteroid-Comet amalgam for a space ship
>design like mine? If I am re-inventing the wheel with my
>*revolutionary* "Ahad-AstroCom" generation starship concept... then
>please tell me!
>
I'm surprised you seem to have missed Eon by Greg Bear. A whole colony
returning to Earth after touring the universe inside an asteroid. It's
a very good book.
Steve
--
EasyNN-plus. The easy way to build neural networks.
Build networks from numeric, text and image files.
http://www.easynn.com
Greg D. Moore (Strider)
<st...@tropheus.demon.co.uk> wrote in message
news:8k8th0hn2t4kir51p...@4ax.com...
>
> I'm surprised you seem to have missed Eon by Greg Bear. A whole colony
> returning to Earth after touring the universe inside an asteroid. It's
> a very good book.
Must have been a small asteroid.
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"Abdul Ahad" <aa_spa...@yahoo.co.uk> wrote in message
news:3416b228.0408...@posting.google.com...
> I wonder if this idea is worth pursuing to further detail. I started
> the thing a while back, but have not had much time to take it forward
> to completion:-
>
>
http://uk.geocities.com/aa_spaceagent/restricted/interstellar-propulsion.html
>
> Has anyone come across an Asteroid-Comet amalgam for a space ship
> design like mine? If I am re-inventing the wheel with my
> *revolutionary* "Ahad-AstroCom" generation starship concept... then
> please tell me!
Pretty close to what was used by the aliens in in "Footfall" by Larry
Niven, and Jerry Pournelle...
David A. Smith
Andrew Plotkin
>
> <st...@tropheus.demon.co.uk> wrote in message
> news:8k8th0hn2t4kir51p...@4ax.com...
> >
> > I'm surprised you seem to have missed Eon by Greg Bear. A whole colony
> > returning to Earth after touring the universe inside an asteroid. It's
> > a very good book.
>
> Must have been a small asteroid.
On the outside, it was, yes.
(Followups reduced)
--Z
"And Aholibamah bare Jeush, and Jaalam, and Korah: these were the borogoves..."
*
* Make your vote count. Get your vote counted.
Androcles
"AA Institute" <abdul...@ntlworld.com> wrote in message
news:adbf5bc1.04081...@posting.google.com...
| > Your optimism is founed upon ignorance.
|
| That's a matter of opinion and based on how flexible people want to be
| about the realm of possibilities. I like to think that my concept is
| not based on *complete* sci-fi, unlke many other ideas floating around
| out there inside people's heads.
Sci-fi, or science fiction, is to write about a possible future in which
some imaginary technological development has taken place and the social
implications that follow. Yours is not complete sci-fi, you've left out the
impact on society. How are we to classify the idea floating around in your
head from the idea floating around inside any renowned science-fiction
author's head? Whatever you like to think, your idea is to pursuade the
human race or some political segment thereof to expend a vast amount of its
resources in capturing an *asteroid*, for heaven's sakes, kitting it out as
a massive spacecraft and going to some unknown destination that just happens
to be nearby, astronomically speaking, gathering fuel that you suspect but
are not certain is along the way. I call that sci-fi, and poorly thought out
sci-fi at that. Finish the book if you want to, and if it has a human
interest angle with heros, heroines, villains and danger it may even get
made into a movie, but it is every bit as much sci-fi as anything I've ever
heard of.
Androcles
James Nicoll
>news:8k8th0hn2t4kir51p...@4ax.com...
>>
>> I'm surprised you seem to have missed Eon by Greg Bear. A whole colony
>> returning to Earth after touring the universe inside an asteroid. It's
>> a very good book.
>
>Must have been a small asteroid.
>
together esp well if you insist on looking at the science.
For example, the original rock used is still recognizable,
so it hasn't been altered all that much on the outside. It's spun for
gravity, about 60% of Earth's, so the exterior is experiencing even
larger forces. Unfortunately the tensile strength of rock is low,
so the whole damn thing should just fly apart.
Also, it ends up in a rather low orbit around Earth (as close as
10,000 km at periapsis) and the tides it raises should be about 10x the
tides the Moon raises on Earth. No sign of this. The tidal forces acting
on the ship are about 55,000x the forces acting on the Moon, and there's
no sign of that, either.
--
Take the piston rings out of my stomach, And the cylinders out of my brain
Extract from my liver the crankshaft, And assemble the engine again!
[from 'The Dying Aviator']
Hex
Sorry, but your ideea is not very useful.
The first reason is that the density of material going further out
decrases very rapidly.
Of course there may be suitable bodies the Kuiper belt and even the
Oort cloud, but you have to understand that most of the mass is
concentrated in the "inner" solar system.
Also, a sphere grows 8 times when you double it's radius. So a 1 ly
sphere would be almost 40 bilion times the volume of a sphere going
all the to Pluto.
It's fairly easy to see that the average mass density is very low, and
goes down quickly as you go out inner solar system.
And another problem with your system is speed... you can't accelerate
continously as you assume.
You might know that cinetic energy Ec=(m*v^2)/2. So cinetic energy of
an object grows geometrically with speed (relative to you). To "catch"
an asteroid, you either match your speed with theirs (and their speed
is pretty small - a few 1000 m/s) so you don't need much energy, or
you go very fast spend that energy to grab it.
If you had that huge amount of energy to spend (think of the energy
involved in a relativly slow-moving, not too big asteroid such as at
Tunguska or Arizona.) you wouldn't be using asteroid catching in the
first place, you'd be cruising along in a high-thrust ion engine...
An asteroid "hoping" scenario might be interesting if you had an
automated probe and wanted to visit each one of them, and would want
to recover your fuel lossess from manuvering and such. It is mainly a
fuel saving tehnique, i can't see it going much faster then Voyager.
AA Institute
What techniques did the aliens use? It sounds very interesting and I'm intrigued.
cheers
Abdul Ahad
David Evens
wrote:
Only atypical ones were modified Bussard ramjet to protect it from
interstellar matter and hybrid generation-sleepership design. There
were two components of the crew, a generational component that looked
after the ship in flight and a sleeper component that was placed in
cryo for the journey (presumably, since they fully intended to launch
an invasion of the inhabited planet upon arrival, they wanted a
substantial number of personel with first-hand knowledge of how to
operate on a planet when they arrived so that the invasion wasn't too
farcial). Other than that, bog-standard worldship: Closed loop
ecology requiring minimal resupply, adaptation of cultural practices
to fit in with a tight recycling of all material wastes, including
dead bodies, multiple inner hulls in case of hull breach, all the
usual stuff.
Alan
and you detect a small comet 6 light-hours dead ahead. You'll be there
in 2 1/2 days. What do you do?
You can't very well collide with the thing, at .1c. Talk about having
a bad day! Capture it? How? At .1c? Or even .0001c? Send a robotic
mining probe ahead, to mine the comet, then accelerate it's mining
output to match your velocity as you fly by? If your robotic probe
could do that in 2 1/2 days, why have you spent so long sitting in
your asteroid-starship, accelerating to .1c?
Let's say you HAVE somehow managed to snag the comet. Now what? You
have "reaction mass" - something to "push back" in order to accelerate
YOU forward. Where do you get the energy to do this? You've just added
to the mass you're trying to accelerate by picking up this comet, and
have used considerable energy matching the comet's velocity to your
own, and now you've got a mountain-sized chunk of ice and rock that
you're going to try to get energy out of?
Gee, if you can do THAT, you could put the oil companies out of
business!
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"AA Institute" <abdul...@ntlworld.com> wrote in message
news:adbf5bc1.04081...@posting.google.com...
Working from my recollection...
They harvested an iceball, to get fusion propulsion mass, to get them up to
the speed that a Bussard ramjet could get them between the stars (to
Earth). The then similarly harvested objects in orbit around Saturn, until
they came and attacked Earth. We used an Orion setup get get some
horsepower into space to stop them.
URL:http://en.wikipedia.org/wiki/Nuclear_pulse_propulsion
URL:http://www.islandone.org/Propulsion/ProjectOrion.html
The aliens ancillary spacecraft propulsion was similar to Orion, but used a
more rapid cycle, fusion pellets, and smaller yield. Presumably, the
mother ship also used this method to get interstellar speed...
David A. Smith
James Nicoll
Alan <gp...@mindless.com> wrote:
>Okay, you're zipping merrily along in your asteroid-starship at .1c,
>and you detect a small comet 6 light-hours dead ahead. You'll be there
>in 2 1/2 days. What do you do?
>
>You can't very well collide with the thing, at .1c. Talk about having
>a bad day! Capture it? How? At .1c? Or even .0001c? Send a robotic
>mining probe ahead, to mine the comet, then accelerate it's mining
>output to match your velocity as you fly by? If your robotic probe
>could do that in 2 1/2 days, why have you spent so long sitting in
>your asteroid-starship, accelerating to .1c?
Well, robots can in theory be made more robust than humans.
The power output implied by braking from 0.1 in 2 1/2 days is pretty
impressive, though.
If I had to use Oort cloud objects in a story I would use one
of the following methods:
1: Islands
No fast transport at all, but if you can use a comet for raw
materials to live off of, you don't need fast transport. As each comet
is settled and filled up, population pressure encourages the slow spread
of humans to other, unoccupied worldlettes. In the pessimistic version,
the inevitable slow leak of volatiles from habitats combined with the
finite size of oort cloud bodies leads to an endless series of Henderson
Islands, stripped of their volatiles, orbited by now lifeless habitats.
2a: Relays
Small robot probes are sent out via snail-drive to set up robust
electromagnetic cannon to fire prepared fuel capsules into the path of
fast, crewed ships.
2b: Relays
The material of the Oort cloud bodies are used to build rectennas
used to relay power from the Sun to the starships.
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"Alan" <gp...@mindless.com> wrote in message
news:847702a8.04081...@posting.google.com...
> Okay, you're zipping merrily along in your asteroid-starship at .1c,
> and you detect a small comet 6 light-hours dead ahead. You'll be there
> in 2 1/2 days. What do you do?
>
> You can't very well collide with the thing, at .1c. Talk about having
> a bad day! Capture it? How? At .1c? Or even .0001c? Send a robotic
> mining probe ahead, to mine the comet, then accelerate it's mining
> output to match your velocity as you fly by? If your robotic probe
> could do that in 2 1/2 days, why have you spent so long sitting in
> your asteroid-starship, accelerating to .1c?
If I had a choice of methods, and a Bussard ramjet, and either I needed the
thrust or it was in the way, I'd fire a solid chunk that I'd accelerated at
it, fast enough to shatter/vaporize the target. Then let the Bussard
fields direct that matter to whereever I needed it.
> Let's say you HAVE somehow managed to snag the comet. Now what? You
> have "reaction mass" - something to "push back" in order to accelerate
> YOU forward. Where do you get the energy to do this?
Fusion,
> You've just added
> to the mass you're trying to accelerate by picking up this comet, and
> have used considerable energy matching the comet's velocity to your
> own, and now you've got a mountain-sized chunk of ice and rock that
> you're going to try to get energy out of?
How do you get thrust from the ISS? You push on it with your feet...
> Gee, if you can do THAT, you could put the oil companies out of
> business!
Mobile fusion power? You bet!
David A. Smith
Tim Auton
[answer further down...]
That bit isn't that hard. Just convert a bit of the mass to energy.
Conceptually it's not hard; but it would take some serious engineering
to make it work at all, let alone at a useful scale.
And putting oil companies out of business would take a lot more than a
better product...
Tim
--
Google is not the only search engine.
David Evens
Actually, the book makes it clear that the main drive of the
mothership used a continuous fusion reaction, not pulsed. However,
while docked the anciliary ships could be used as auxilary thrusters,
which says interesting things about the strength of their docking
clamps.
AA Institute
>
> Sorry, but your ideea is not very useful.
> The first reason is that the density of material going further out
> decrases very rapidly.
> Of course there may be suitable bodies the Kuiper belt and even the
> Oort cloud, but you have to understand that most of the mass is
> concentrated in the "inner" solar system.
I hear what you say and I think when you say "inner" solar system, you
mean the solar system as far as we define its boundaries within the
heliopause and such like (i.e. as far as we can *see* material objects
beyond the orbit of Pluto).
The conventional view that I always had of the solar system coalescing
into the Sun and nine planets from a flattened proto-planetary disk,
always supports the view that the bulk of the mass should always be
concentrated towards the centre. So how come the gas giants (Jupiter,
Saturn, Uranus and Neptune) are in the *outer* solar system and the
tiddler terrestrial planets are in the *inner* solar system? Probably
through some random irregularities in the uniformity of the
proto-planetary disk? I always had a common sense notion that
F=G(m1*m2)/r^2 would dictate the massive planets to be further in than
they are.
In theory, the force of gravity is *infinite* in its reach (F <> 0
until r = infinity), hence the Sun's sphere of influence goes as far
as Alpha Centauri and beyond... albeit the strength falling off
rapidly in line with the inverse square law. Hence you would expect
the bulk of the mass to concentrate near the centre of our solar
system (which it does, generally). But the Sun has made some 20
revloutions around the Milky Way galaxy since its formation (4,500
million / 225 million years). Within that time, it has passed through
dense gas clouds, star and planet forming regions, brushing the outer
edges of proto-planetary disks of other stars, attracting and shedding
swarms of comets, it may even have swapped planets with other stars
(are we certain that Pluto is a *native* member of our own solar
systeme???) etc. etc.
There is every reason to suppose there may be swarms of comets out
there, where the solar illumination is too tiny and the cosmic night
sky's miniscule flux of 1/300th of a full moon light illumination
(thanks to my own little evaluation!) is too tiny to enable visual
detection by current telescopes.
> Also, a sphere grows 8 times when you double it's radius. So a 1 ly
> sphere would be almost 40 bilion times the volume of a sphere going
> all the to Pluto.
> It's fairly easy to see that the average mass density is very low, and
> goes down quickly as you go out inner solar system.
That's to be expected of course based on elementary Maths relating
radius to volume.
> And another problem with your system is speed... you can't accelerate
> continously as you assume.
It will have to be a *slow* route to the stars, hence the need for
this to be a "generation" starship of a miniature *world* size, which
makes it a hollowed out asteroid as probably one easy solution. Why
invent cheap imitations when nature has already provided ways and
means?
Perhaps an asteroid of #243 Ida's mass and density is too tall an
order for a starship design, but what would be a better solution is a
lower density asteroid that is perhaps of a class known as an 'Earth
approacher' rather than a 'main belt' asteroid candidate. That would
be easier to excavate if its of a lower density and if its of a lower
mass, then relatively easier to change its orbit.
Grimble Gromble
news:cfogl9$9a4$1...@panix2.panix.com...
> If I had to use Oort cloud objects in a story I would use one
> of the following methods:
>
> 1: Islands
>
> No fast transport at all, but if you can use a comet for raw
> materials to live off of, you don't need fast transport. As each comet
> is settled and filled up, population pressure encourages the slow spread
> of humans to other, unoccupied worldlettes. In the pessimistic version,
> the inevitable slow leak of volatiles from habitats combined with the
> finite size of oort cloud bodies leads to an endless series of Henderson
> Islands, stripped of their volatiles, orbited by now lifeless habitats.
>
> 2a: Relays
>
> Small robot probes are sent out via snail-drive to set up robust
> electromagnetic cannon to fire prepared fuel capsules into the path of
> fast, crewed ships.
>
> 2b: Relays
>
> The material of the Oort cloud bodies are used to build rectennas
> used to relay power from the Sun to the starships.
Because exponential growth will always outstrip polynomial growth at some
stage, humans (who tend to reproduce exponentially) will inevitably exhaust
any supplies they can reach (cubic polynomial even at the speed of light)
and are going to have to control their population sooner or later. Why not
sooner?
Grim
Sander Vesik
You would probably find them with radar. Large flimsy structures
and all that. Making use of them is of course a different and rather
interesting trick.
--
Sander
+++ Out of cheese error +++
Ian Stirling
Radar doesn't really work very well at extreme ranges.
r^4 is nasty.
Alfred A. Aburto Jr.
Arecibo works well within the Solar System ... out to 5 AU I suppose ...
More powerful radars could be built and used of course at the outskirts of
the Solar System.
Also, optical telescopes such as Hubble can detect Kuiper Belt Objects from
Earth (40-50AU away)...
So optical detection & tracking is not out off the table either...
The good point about the suggestion from Abdul Ahad is to take advantage of
the natural resources (comets & planetoids (KBO's)) in interstellar space to
travel between the stars. When you build the interstellar vehicle out near
Pluto you won't need to take all your supplies (water, fuel, ..., etc.) with
you ... you can find it in the Oort Cloud comets (and probably planetoids
too!) along the way. Who cares if it takes a million years to travel between
stars! --- Earth is a spaceship anyway, it has already traveled through
space for almost 5 billion years. Only "problem" is that is is locked
(trapped) in orbit around the Sun.... we can solve this problem if we put
our minds to it. We need a long range plan though (it may take hundreds of
years to complete perhaps) ...
(1) chart the orbits of the comets & planetoids (KBO's, or whatever we call
those objects) (there are trillions of these out there)
(2) determine the physical & chemical properties of these comets &
planetoids and given that,
(3) figure out how to use those materials for water, food, fuel, and perhaps
materials for the spaceship ...
I think it is a great idea ...
Al
Bill Hobba
"N:dlzc D:aol T:com (dlzc)" <N: dlzc1 D:cox T:n...@nospam.com> wrote in
message news:SoPTc.63339$xk.26852@fed1read01...
The Orien's? Are they not the killer loudspeakers designed by renowned
engineer Seigfreid Linkwitz http://www.linkwitzlab.com/?
Thanks
Bill
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"Bill Hobba" <bho...@rubbish.net.au> wrote in message
news:fZfUc.194$R7....@news-server.bigpond.net.au...
No. They could never get over the high speed of sound in space! The
sounds of threats by Alvin and the Chipmunks did not provoke the fear they
were expecting...
David A. Smith
Rob Dekker
Finally somebody who makes some sense.
Getting fuel along the way is useless if you have to accellerate it to your own speed any way.
Energy-wise, it costs the same as if you would bring it with you from earth.
And then you could bring the right 'stuff' also, and not have the risk factor of finding only useless material in the Oort cloud.
No. I think we should first invent well-working nuclear fusion before we can think about any interstellar travel.
And we need that any way, since the planet is rapidly running out of oil.
Rob
"Alan" <gp...@mindless.com> wrote in message news:847702a8.04081...@posting.google.com...
Ian Stirling
It works well for mapping planets that you are pretty sure are there.
It doesn't work so well for detecting smaller bodies that you don't
know where they are.
Take Arecebo for example.
It's 300m.
Say you'r using 30Ghz, so the beamwidth is around .01m/300m.
Or 3*10^-5 radians.
So the beam area is some 7*10^-10 radians squared.
This is a gain of about 10^12 over an omnidirectional antenna.
However, for small objects (where the beam size is much larger than
the object) this only takes you to about (10^12)^0.25 = 1000 times
further than an omnidirectional antenna.
To get a million times further needs a dish not 300Km, but 300000Km across.
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"Rob Dekker" <r...@verific.com> wrote in message
news:RKgUc.7032$ps3....@newssvr29.news.prodigy.com...
>
> Finally somebody who makes some sense.
>
> Getting fuel along the way is useless if you have to accellerate it to
your own speed any way.
> Energy-wise, it costs the same as if you would bring it with you from
earth.
> And then you could bring the right 'stuff' also, and not have the risk
factor of finding only useless material in the Oort cloud.
>
> No. I think we should first invent well-working nuclear fusion before we
can think about any interstellar travel.
> And we need that any way, since the planet is rapidly running out of oil.
We have nuclear fusion now. What we cannot do is keep it running on Earth,
due to the huge number of neutrons produced. It is far dirtier than
fission, for the amount of power produced, and scaling up will not much
improve this. So the best place for fusion is in the Sun, where great
quantities of matter, and distance, can shield us. And the poisoned
structures aren't left sitting about, radiating back to near background.
David A. Smith
Paul F. Dietz
> We have nuclear fusion now. What we cannot do is keep it running on Earth,
> due to the huge number of neutrons produced. It is far dirtier than
> fission, for the amount of power produced, and scaling up will not much
> improve this.
This is bullshit. The large number of neutrons produced is not the
reason we 'can't keep it running', and fusion is not dirtier than fission.
Most of the waste from the latter is from fission products and transuranics,
not from neutron activation of reactor structure. The long-lived radioactive
burden from a DT fusion reactor is orders of magnitude smaller than from
a fission reactor of the same power.
We don't have fusion because building an economical fusion reactor
is simply a difficult problem.
Paul
Martin 53N 1W
> N:dlzc D:aol T:com (dlzc) wrote:
>
>> We have nuclear fusion now. What we cannot do is keep it running on
>> Earth,
>
> We don't have fusion because building an economical fusion reactor
> is simply a difficult problem.
Look up ITER:
http://www.iter.org/
Not that far away once a site has been agreed...
http://www.iter.org/ITERPublic/ITER/pics/construction.jpg
Regards,
Martin
--
---------- OS? What's that?!
- Martin - To most people, "Operating System" is unknown & strange.
- 53N 1W - Mandrake 10.0.1 GNU Linux
---------- http://www.mandrakelinux.com/en-gb/concept.php3
Paul Blay
> Paul F. Dietz wrote:
>> N:dlzc D:aol T:com (dlzc) wrote:
>>
>>> We have nuclear fusion now. What we cannot do is keep it running on
>>> Earth,
>>
>> is simply a difficult problem.
>
> Look up ITER:
> http://www.iter.org/
"to aim at demonstrating steady-state operation using non-inductive current
drive with a ratio of fusion power to input power for current drive (Q) of at
least 5."
... would appear to be one of the most relevant bits. Of course it does say
"to aim at". And 'economical' is _not_ one of the aims.
AA Institute
> "AA Institute" <abdul...@ntlworld.com> wrote in message
> news:adbf5bc1.04081...@posting.google.com...
> | > Your optimism is founed upon ignorance.
> |
> | That's a matter of opinion and based on how flexible people want to be
> | about the realm of possibilities. I like to think that my concept is
> | not based on *complete* sci-fi, unlke many other ideas floating around
> | out there inside people's heads.
>
>
> Sci-fi, or science fiction, is to write about a possible future in which
> some imaginary technological development has taken place and the social
> implications that follow. Yours is not complete sci-fi, you've left out the
> impact on society. How are we to classify the idea floating around in your
> head from the idea floating around inside any renowned science-fiction
> author's head? Whatever you like to think, your idea is to pursuade the
> human race or some political segment thereof to expend a vast amount of its
> resources in capturing an *asteroid*, for heaven's sakes, kitting it out as
> a massive spacecraft and going to some unknown destination that just happens
> to be nearby, astronomically speaking, gathering fuel that you suspect
Lighten up... we aren't about to fly to the stars! There's the new
vision of space set out by George W. Bush, the so-called "Moon to
Mars" initiative which is currently forcing NASA to restructure itself
by way of re-alignment to facilitate that vision. Hopefully by 2020,
if we're lucky we will see astronauts doing some joy riding on the
Moon! I dream of that day (my generation was too young to remember
even the very last mission - Apollo 17 - on the Moon).
> Finish the book if you want to, and if it has a human
> interest angle with heros, heroines, villains and danger it may even get
> made into a movie, but it is every bit as much sci-fi as anything I've ever
> heard of.
Writing a sci-fi novel around a trip to Alpha Centauri in a generation
starship sounds an excellent idea and I have imagined some of it
already. If anyone beats me to it, please can you remember to add some
supernatural horror, as I'm into all that spine chilling stuff. A sort
of "Arthur C. Clarke meets Stephen King" would be ideal...
Interstellar cosmic darkness shrouding a lonely colony of generation
starship occupants is a perfect setting for such a novel. Where
creatures of pure energy roam between solar systems... interacting
with the minds of starship dwellers... <snip> (I don't want to give
the story away!!!)
Androcles
Get with the program. This idea isn't mine, now is it?
| There's the new
| vision of space set out by George W. Bush, the so-called "Moon to
| Mars" initiative which is currently forcing NASA to restructure itself
| by way of re-alignment to facilitate that vision. Hopefully by 2020,
| if we're lucky we will see astronauts doing some joy riding on the
| Moon! I dream of that day (my generation was too young to remember
| even the very last mission - Apollo 17 - on the Moon).
I'm not that young. I well remember the cold war days when we lived under
the very real threat of world wide nuclear destruction, the Cuban missile
crisis and the race to the moon. I even remember Sputnik and Telstar, and
that the Russians were capable of launching spy satellites. The race to
space was about survival, not glory.
|
| > Finish the book if you want to, and if it has a human
| > interest angle with heros, heroines, villains and danger it may even get
| > made into a movie, but it is every bit as much sci-fi as anything I've
ever
| > heard of.
|
| Writing a sci-fi novel around a trip to Alpha Centauri in a generation
| starship sounds an excellent idea and I have imagined some of it
| already. If anyone beats me to it,
Oh come on... it's been done. Haven't you read any sci-fi? Larry Niven and
Jerry Pournelle's "Mote in God's Eye" for example. Or "Eon"? Even nearly
Asimov with a cop jaunting off to the planet Aurora? That shouldn't stop
you writing another, though. There is always a demand for new fiction.
| please can you remember to add some
| supernatural horror, as I'm into all that spine chilling stuff. A sort
| of "Arthur C. Clarke meets Stephen King" would be ideal...
Me? I'm not adding anything. It's your yarn, not mine.
You should remember that it was Clarke that dreamt up the communications
satellite. King you can keep, supernatural doesn't interest me.
Androcles.
Grimble Gromble
> In theory, the force of gravity is *infinite* in its reach (F <> 0
> until r = infinity),
That only works in Newtonian gravity where the 'speed' of the gravitational
influence is infinite. In General Relativity, the speed is limited to that
of light. It can only influence infinitely distant objects if it has an
infinte amount of time to do so.
Grim
Grimble Gromble
news:RKgUc.7032$ps3....@newssvr29.news.prodigy.com...
> Getting fuel along the way is useless if you have to accellerate it to
your own speed any way.
> Energy-wise, it costs the same as if you would bring it with you from
earth.
What you pick up gets used as reaction mass rather than fuel per se. As long
as you can push it out the back faster than it comes in the front, you're in
business. Jets work by adding a little heat from fuel in the tanks to air
picked up in transit. If you can get energy out of your reaction mass, which
you can with fusion, then you don't need to carry any fuel with you.
Grim
Benign Vanilla
>
> "Abdul Ahad" <aa_spa...@yahoo.co.uk> wrote in message
> news:3416b228.0408...@posting.google.com...
> | I wonder if this idea is worth pursuing to further detail. I started
> | the thing a while back, but have not had much time to take it forward
> | to completion:-
> |
> |
>
http://uk.geocities.com/aa_spaceagent/restricted/interstellar-propulsion.html
> |
> | Has anyone come across an Asteroid-Comet amalgam for a space ship
> | design like mine? If I am re-inventing the wheel with my
> | *revolutionary* "Ahad-AstroCom" generation starship concept... then
> | please tell me!
> |
> |
> | cheers,
> |
> | Abdul Ahad
>
| --------------------------------------------------------------------------
> ---
> | http://uk.geocities.com/aa_spaceagent/
> | "We have lingered long enough on the shores of the cosmic ocean. We
> | are ready at last to set sail for the stars"........Carl Sagan
>
| --------------------------------------------------------------------------
> ---
> I would recommend a disposable probe first. As you've pointed out, The
> energy required will be astronomical, and energy = money. Who is paying
and
> what is the payback expected?
My first impressions are that firstly, we'll have to wait for a few comets
to come by before this could work. Then, we will need to expel massive
amounts of energy to capture the comets and bring them to the earth. Then
once we do that, we repeat for the asteroid. Now we strap this whole thing
together, and then spend even more massive amounts of energy to get the ship
out of earth's orbit.
Why not just build a ship in orbit and launch from there?
BV.
Alfred A. Aburto Jr.
I think the Arecibo radar works at 470MHz ...
30GHz is far too high for the surface accuracy ...
In a phased radar the beam pointing would be guided electronically ...
There are many possibilities ... I don't believe hopeless is one of them :-)
Al
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"Paul F. Dietz" <di...@dls.net> wrote in message
news:FeWdnayR6Z0...@dls.net...
> N:dlzc D:aol T:com (dlzc) wrote:
>
> > We have nuclear fusion now. What we cannot do is keep it running on
Earth,
> > due to the huge number of neutrons produced. It is far dirtier than
> > fission, for the amount of power produced, and scaling up will not much
> > improve this.
>
> This is bullshit. The large number of neutrons produced is not the
> reason we 'can't keep it running', and fusion is not dirtier than
fission.
Okay, let's see if I can say this in a more pollitically correct way. The
very high temperatures require low nearby masses. Since shielding must be
further away, more volume of it is required. Fusion does produce lots of
neutrons (on a kg per kg basis), and the first thing neutrons hit is
structure and "drive"... not shielding. You are right, in that currently,
containment of the plasma is the hard step. Beyond this, is disposal of
the works that is bombarded by neutrons, which necessarily located inside
the shielding.
> Most of the waste from the latter is from fission products and
transuranics,
> not from neutron activation of reactor structure. The long-lived
radioactive
> burden from a DT fusion reactor is orders of magnitude smaller than from
> a fission reactor of the same power.
>
> We don't have fusion because building an economical fusion reactor
> is simply a difficult problem.
Agreed.
David A. Smith
Paul F. Dietz
> Okay, let's see if I can say this in a more pollitically correct way. The
> very high temperatures require low nearby masses. Since shielding must be
> further away, more volume of it is required. Fusion does produce lots of
> neutrons (on a kg per kg basis), and the first thing neutrons hit is
> structure and "drive"... not shielding. You are right, in that currently,
> containment of the plasma is the hard step. Beyond this, is disposal of
> the works that is bombarded by neutrons, which necessarily located inside
> the shielding.
That's nice. Your statement that it is 'far dirtier than fission'
is still utter bullshit.
Paul
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"Paul F. Dietz" <di...@dls.net> wrote in message
news:qpadndhJLZc...@dls.net...
They were still toying with the idea of using a fusion facility for a few
months, then abandoning it until it "cooled down". A nuclear reactor
facility, even a fusion one, cannot be easily hauled off and buried
underground. Will you settle for "may end up being as dirty as fission"?
David A. Smith
Paul F. Dietz
>>That's nice. Your statement that it is 'far dirtier than fission'
>>is still utter bullshit.
>
>
> They were still toying with the idea of using a fusion facility for a few
> months, then abandoning it until it "cooled down". A nuclear reactor
> facility, even a fusion one, cannot be easily hauled off and buried
> underground. Will you settle for "may end up being as dirty as fission"?
No. The quantity of long-lived nuclear waste produced is orders of
magnitude less than in a fission reactor of similar capacity.
I'll settle for your admission that your original statement was completely
wrong. Deal?
Paul
David Evens
dlzc1 D:cox T:n...@nospam.com> wrote:
>Dear Paul F. Dietz:
>
>"Paul F. Dietz" <di...@dls.net> wrote in message
>news:FeWdnayR6Z0...@dls.net...
>> N:dlzc D:aol T:com (dlzc) wrote:
>>
>> > We have nuclear fusion now. What we cannot do is keep it running on
>Earth,
>> > due to the huge number of neutrons produced. It is far dirtier than
>> > fission, for the amount of power produced, and scaling up will not much
>> > improve this.
>>
>> This is bullshit. The large number of neutrons produced is not the
>> reason we 'can't keep it running', and fusion is not dirtier than
>fission.
>
>Okay, let's see if I can say this in a more pollitically correct way. The
>very high temperatures require low nearby masses. Since shielding must be
>further away, more volume of it is required. Fusion does produce lots of
>neutrons (on a kg per kg basis), and the first thing neutrons hit is
>structure and "drive"... not shielding. You are right, in that currently,
>containment of the plasma is the hard step. Beyond this, is disposal of
>the works that is bombarded by neutrons, which necessarily located inside
>the shielding.
The high neutron flux if primarily the result of the fact that most
experimental rigs use the easiest fuel possible: A mix of deterium
and tritium, which produces a neutron flux dependant on the ratios;
or, a mix including helium-3. This is infeasiable as the fuel for any
sort of commercial plant, particularly tritium, which is a byproduct
of heavy-water fission reactor systems, which you presumably want to
replace with fussion systems, and is available in only very, very
small ammounts anyway. Helium-3 is damnably hard to get ahold of
insignificant quantities as well. The stuff flatly doesn't occur in
nature on this planet any more that tritium does. A practicle
commercial plant is pretty much going to have to use the CNO process
simply to be able to get enough fuel at rational prices.
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"Paul F. Dietz" <di...@dls.net> wrote in message
news:PfqdnUz-zs0...@dls.net...
No deal. Not if you leave an entire "hot" reactor behind... And you had
to qualify with "long-lived" anyway! ;>)
David A. Smith
Paul F. Dietz
>>I'll settle for your admission that your original statement was
>
> completely
>
>>wrong. Deal?
>
>
> No deal. Not if you leave an entire "hot" reactor behind... And you had
> to qualify with "long-lived" anyway! ;>)
The fact that the waste is 1000x less than from a fission reactor
after 10 years is rather relevant, no?
Still going to hold out on admitting your original statement was full of shit?
Paul
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"Paul F. Dietz" <di...@dls.net> wrote in message
news:1-idnWsXdZ-...@dls.net...
You've got a functioning fusion reactor, as a source for your "facts"?
1000x times less from a reactor that is "one shot", and puts out
1/100,000th the energy in a year (if that). So who is full of shit now
Paul?
Are you selling stock or what? Don't worry about me, I'm an Idiot.
David A. Smith
Ian Stirling
So it's almost a factor of 100 worse.
>
> In a phased radar the beam pointing would be guided electronically ...
>
> There are many possibilities ... I don't believe hopeless is one of them :-)
Unfortunately, the universe does not care about your beliefs.
You cannot guide a beam electronically to a finer beam than the size of
the apature.
Martin 53N 1W
> shit?
>
> You've got a functioning fusion reactor, as a source for your "facts"?
> 1000x times less from a reactor that is "one shot", and puts out
> 1/100,000th the energy in a year (if that). So who is full of shit now
> Paul?
>
> Are you selling stock or what? Don't worry about me, I'm an Idiot.
Google or read up a few facts to be less of an Idiot then...
Conventional coal fired power stations have and produce more
radioactivity than a comparable nuclear fission plant. The coal fired
plant makes a vast mess also... (Hint: coal is radioactive and you
consume vast volumes of the stuff.)
For a fusion reactor, the only radioactive 'waste' of concern are the
irradiated reactor components when the plant is decommissioned.
There's lots more info easily available to push back your boundaries of
ignorance a little farther.
Good luck,
Paul F. Dietz
> You've got a functioning fusion reactor, as a source for your "facts"?
Ah, so your position is that we cannot estimate the activation of
a reactor without actually building one?
So the source of your original comment was... what?
You'll generally appear less idiotic if you don't outright contradict
yourself, fool.
Paul
Paul F. Dietz
> 1000x times less from a reactor that is "one shot", and puts out
> 1/100,000th the energy in a year (if that). So who is full of shit now
> Paul?
Look, for example, at the PULSAR-I design study. This reactor design
(a 1000 MW(e) reactor) uses mostly SiC for the reactor structure
(shield and blanket).
Decay heat in this design at shutdown is about 19 MW (vs. perhaps 200 MW
in a fission reactor of similar capacity). The decay heat falls
rapidly, to a bit over 1 kW in 1 week. The integrated decay energy
in the reactor structure over 1 week is only about 10 GJ. This makes
the design immune to meltdown due to decay heat, even in the event
of complete loss of all cooling capacity at reactor shutdown.
In contrast, the integrated decay heat from the fission reactor of
the same capacity is about three orders of magnitude larger than
his over that period. The total decay power at 1 week is roughly
5000 times larger.
Other first wall materials (such as vanadium) have a somewhat larger
short term activation than SiC, but lower long term activation. Vanadium
from a used-up first wall could be a 'hands-on' material after a few decades,
and class-C rad waste not long after. Most likely it would be recycled.
Paul
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"Paul F. Dietz" <di...@dls.net> wrote in message
news:w4SdnfRDLb6...@dls.net...
Thanks! I take back my "much dirtier" comment. I was wrong.
David A. Smith
Russell Wallace
<grimble...@virgin.net> wrote:
>Because exponential growth will always outstrip polynomial growth at some
>stage, humans (who tend to reproduce exponentially) will inevitably exhaust
>any supplies they can reach (cubic polynomial even at the speed of light)
>and are going to have to control their population sooner or later. Why not
>sooner?
We're all going to die sooner or later; why not sooner? The answer is
the same in both cases: later is better if one regards life as having
positive value, sooner is better if one regards it as having negative
value. Since you're clearly in the second category, by all means take
action accordingly.
--
"Sore wa himitsu desu."
To reply by email, remove
the small snack from address.
Paul F. Dietz
> Thanks! I take back my "much dirtier" comment. I was wrong.
I take back the insults, which were uncalled for.
Paul
Alfred A. Aburto Jr.
No it is not worse, the beam width is wider ... about a degree or so ...
>
> >
> > In a phased radar the beam pointing would be guided electronically ...
> >
> > There are many possibilities ... I don't believe hopeless is one of them
:-)
>
>
> Unfortunately, the universe does not care about your beliefs.
True ... but then I care about humans more than the universe itself :-)
>
> You cannot guide a beam electronically to a finer beam than the size of
> the apature.
The phased array would allow _steering_ the beam electronically. That is
you could very rapidly scan a small sector of space ... or you could form
multiple beams (even hundreds to scan a large portion of space at once!).
As I said if we put our minds to work, we can solve this problem!
I'd wager, if we ever do space traveling, it will take advantage of the
resources found between the stars, as has been indicated here ...
Ian Stirling
Yes, it's worse.
If you widen the beam to a degree or so from 1/100th of a degree, then
you reduce the beam intensity by a factor of 10000.
If you reduce the intensity by a factor of 10000, you reduce the
energy reflected by the object by a factor of 10000.
This means that for a given sensitivity, the object to be sensed needs
to be sqrt(10000) or 100 times closer.
>> > In a phased radar the beam pointing would be guided electronically ...
>> >
>> > There are many possibilities ... I don't believe hopeless is one of them
> :-)
>>
>>
>> Unfortunately, the universe does not care about your beliefs.
>
> True ... but then I care about humans more than the universe itself :-)
>> You cannot guide a beam electronically to a finer beam than the size of
>> the apature.
> The phased array would allow _steering_ the beam electronically. That is
> you could very rapidly scan a small sector of space ... or you could form
> multiple beams (even hundreds to scan a large portion of space at once!).
> As I said if we put our minds to work, we can solve this problem!
It works well for short ranges, where the time to move a dish is much,
much larger than the time to bounce a pulse off the target.
It's a bit less relevant where you'r waiting hours for a bounce.
Greg D. Moore (Strider)
"N:dlzc D:aol T:com (dlzc)" <N: dlzc1 D:cox T:n...@nospam.com> wrote in
message news:95JUc.106416$xk.14823@fed1read01...
> Dear Paul F. Dietz:
>
> Thanks! I take back my "much dirtier" comment. I was wrong.
>
And other than failing to snip, you've just raised your stock around here.
Seeing someone admit they were wrong is a rare and welcome occurance.
> David A. Smith
>
>
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"Paul F. Dietz" <di...@dls.net> wrote in message
news:yZednYrgouH...@dls.net...
> N:dlzc D:aol T:com (dlzc) wrote:
>
> > Thanks! I take back my "much dirtier" comment. I was wrong.
>
> I take back the insults, which were uncalled for.
Do not! It is frequently necessary to "adjust one's psyche". When nature
needs your attention, she breaks a leg... or worse.
My "feelings" are my problem. Your assignations of bullshit were not
"delivered" to me, but to what I said. I did not feel personally attacked,
only my veracity questioned. Validly questioned.
I really liked the touch where you provided enough keywords to help
"posterity" do a search on current technologies. It is truly appreciated.
David A. Smith
AA Institute
I use *infinite* reach as only a point of notional illustration. If
the Sun's gravity reaches just half way out to Alpha Centauri (2.2
light years) then the total gravity coming from Alpha Centauri's two
principal suns (A and B) with a combined mass of 2.0 x solar mass will
more than meet us half way.
If the theory of an Oort cloud revolving around our Sun proves correct
and common amongst other stars, then it is possible that Alpha
Centauri's own Oort cloud could be bigger than ours and reach out
further, since its extent is likely to be a function of mass/gravity.
I respect Jan Hendrik Oort's judgements in theorising this
'hypothetical' comet cloud which we've yet to find ... I think he was
a distinguished astronomer in his era!
Grimble Gromble
"Russell Wallace" <wallacet...@eircom.net> wrote in message
news:41236758....@news.eircom.net...
> On Mon, 16 Aug 2004 18:10:02 GMT, "Grimble Gromble"
> <grimble...@virgin.net> wrote:
>
> >Because exponential growth will always outstrip polynomial growth at some
> >stage, humans (who tend to reproduce exponentially) will inevitably
exhaust
> >any supplies they can reach (cubic polynomial even at the speed of light)
> >and are going to have to control their population sooner or later. Why
not
> >sooner?
>
> We're all going to die sooner or later; why not sooner? The answer is
> the same in both cases: later is better if one regards life as having
> positive value, sooner is better if one regards it as having negative
> value. Since you're clearly in the second category, by all means take
> action accordingly.
You would appear to have equated two answers to two different questions for
no good reason and also reached an erroneous conclusion regarding my own
perception of the value of life.
Regardless of ones assessment of the value of life, such value is more than
likely to decrease with increasing population, at least beyond a point which
I suspect we have already reached given the present constraints on space and
resources.
I wonder if the action you would have me take would consist of massacring at
least 5 billion humans? My preferred method would be voluntary birth
control. I have already taken such action as I have no intention of further
burdening the planet with any offspring.
Grim
Grimble Gromble
news:adbf5bc1.0408...@posting.google.com...
> If no part of human society ever manages to leave the cradle of our
> solar system and we face extinction here where we were born, then
> that's bound to be regarded as a deep tragedy from a universal
> perspective. Those of us who believe the scientific processes of our
> evolution, we crawled out of the oceans as tiny amphibians... swung on
> trees... developed consciousness and intelligence...looked at billions
> of worlds out in the cosmos through our telescopes... only to face
> extinction in the end knowing we had every chance to throw our seeds
> further out to safety. And why? Because we did not want to send our
> sons and daughters out on a daring voyage into the risky environment
> of interstellar space... Doesn't sound right to me. We send our brave
> soldiers to battle fields every year knowing there is every chance
> they might not make it back.
More's the pity. Imagine what kind of space program (or any kind of program)
we could build if we didn't waste so much on weaponry. Of course, any
'safety' would only be temporary, unless it buys us sufficient time to
figure out how to beat entropy.
Grim
Tim Auton
[snip]
>Because exponential growth will always outstrip polynomial growth at some
>stage, humans (who tend to reproduce exponentially)
The evidence (birth rates in the most developed nations) seems to
disprove your exponential growth theory.
Tim
--
Google is not the only search engine.
Russell Wallace
<grimble...@virgin.net> wrote:
>Regardless of ones assessment of the value of life, such value is more than
>likely to decrease with increasing population, at least beyond a point which
>I suspect we have already reached given the present constraints on space and
>resources.
It turns out to be the other way around - to a fair approximation, the
reason there is evil in the world is because our species evolved in
K-selection conditions, and hasn't yet made the transition to
r-selection.
>I wonder if the action you would have me take would consist of massacring at
>least 5 billion humans? My preferred method would be voluntary birth
>control. I have already taken such action as I have no intention of further
>burdening the planet with any offspring.
Actually, I think your action is the most appropriate one given your
beliefs. Evolution has to operate, but we do have some choices about
how inhumane it has to be.
vonroach
<tim....@uton.groupSexWithoutTheY> wrote:
>"Grimble Gromble" <grimble...@virgin.net> wrote:
>[snip]
>>Because exponential growth will always outstrip polynomial growth at some
>>stage, humans (who tend to reproduce exponentially)
>
>The evidence (birth rates in the most developed nations) seems to
>disprove your exponential growth theory.
>
>
>Tim
How are you defining `polynomial' growth? 2 parents and 1 child is
`exponential growth' ? Is the exponent negative? I hazard a guess that
too much food and prosperity without war, disease, and starvation are
the cause. Exponential growth of bacteria with plenty of food is one
gives two and so on.
AA Institute
> In sci.space.policy Alfred A. Aburto Jr. <abu...@sbcglobal.net> wrote:
> <snip>
> > Yes, there is reason. The Oort Cloud of comets go well beyond the
> > heliopause.
> > The Oort Cloud of comets may extend out to 100,000 AU --- maybe 3 light
> > years from the Sun. This is a good fraction of the way to the nearest star.
>
That's a very interesting point. The theoretical Oort cloud is thought
to exist at some 30,000 to 50,000 AUs out from the Sun. This is way
way beyond the 11,500 AUs (the "Ahad radius"!) determined as a
limiting distance for *solar* illumination of objects.
Technically, as I've determined in my recent paper, any obect existing
at the distance of the Oort cloud would only be illuminated by "star
light", with a miniscule flux of approx. 14 milli-Watt / m^2 of flux
coming from the interstellar night sky.
This is one of the reasons why I feel we might never be able to
visually detect debris floating around in the Oort cloud using solar
system based telescopes, unless the optical sensitivity of current
detectors improves beyond all proportions.
However, since we are talking futuristic technology here, a generation
starship could be kitted up with powerful, wide beam lasers mounted on
its exterior body, which could be used to temporarily act as long
range "flash lights" that selectively light up the AsterCom starship's
forward path and illuminate any oncoming target comets / ice balls.
Since these objects are likely to be "icy" in their compositions at
that distance, away from any star (with high albedos) they would show
up for thousands of miles up a ahead in the torch beam, lighting up
the ship's path like an airport runway lit at night for an aircraft
coming into land.
Abdul Ahad
Tim Auton
>On Fri, 20 Aug 2004 22:48:12 +0100, Tim Auton
><tim....@uton.groupSexWithoutTheY> wrote:
>>"Grimble Gromble" <grimble...@virgin.net> wrote:
>>[snip]
>>>Because exponential growth will always outstrip polynomial growth at some
>>>stage, humans (who tend to reproduce exponentially)
>>
>>The evidence (birth rates in the most developed nations) seems to
>>disprove your exponential growth theory.
>>
>`exponential growth' ? Is the exponent negative? I hazard a guess that
>too much food and prosperity without war, disease, and starvation are
>the cause. Exponential growth of bacteria with plenty of food is one
>gives two and so on.
My point was that population growth (ignoring immigration) is
approximately zero in the most developed nations. It's exponential
growth with an exponent of 1, if you want to put it that way. In other
words: I find the idea that humans will continue to breed and increase
the population ad-infinitum, outstripping all available resources,
somewhat unlikely.
vonroach
Wallace) wrote:
> Evolution has to operate, but we do have some choices about
>how inhumane it has to be.
Your delusion.
vonroach
<tim....@uton.groupSexWithoutTheY> wrote:
Tim, your figuring is handicapped by some mathematical deficits. An
exponent of `1' doesn't give exponential growth. Also reproduction is
a natural response to an instinct and all your figgering hasn't got a
ghost of a chance against inborn nature.
If you want to `control' population just turn your back and ignore
poverty, starvation, disease, and war - then nature can control it
naturally in the usual manner.
Most misguided effort of 20th century was `battle' to overcome birth
defects and prematurity which pollutes the gene pool and is a more
futile `battle' than that against drug abuse and perversions (which by
your figgering, are both contributors to control). Let AIDS go, the
bisexuals also contribute to over population.
Also sending good genes to fight for bad genes in the Eastern
Hemisphere from which the good genes escaped is not such a wise policy
lest we end up with the same cowardly genes found in Europe, Mideast,
and Africa. Now are you ready to seriously confront the problem or do
you want to toy with exponents and political correctness?
Paul F. Dietz
> Tim, your figuring is handicapped by some mathematical deficits. An
> exponent of `1' doesn't give exponential growth. Also reproduction is
> a natural response to an instinct and all your figgering hasn't got a
> ghost of a chance against inborn nature.
> If you want to `control' population just turn your back and ignore
> poverty, starvation, disease, and war - then nature can control it
> naturally in the usual manner.
> Most misguided effort of 20th century was `battle' to overcome birth
> defects and prematurity which pollutes the gene pool and is a more
> futile `battle' than that against drug abuse and perversions (which by
> your figgering, are both contributors to control). Let AIDS go, the
> bisexuals also contribute to over population.
> Also sending good genes to fight for bad genes in the Eastern
> Hemisphere from which the good genes escaped is not such a wise policy
> lest we end up with the same cowardly genes found in Europe, Mideast,
> and Africa. Now are you ready to seriously confront the problem or do
> you want to toy with exponents and political correctness?
>
Jeez, I thought your brand of eugenic racism went out of style in 1945.
BTW, your first paragraphs there are directly contrary to evidence.
The countries with the high standards of living, peace, and good
health care have low fertility rates and soon will have declining
populations. But bigots and misanthropes don't let facts get in
the way of a good hate-filled spew, do they?
Paul
Tim Auton
>On Sat, 21 Aug 2004 22:12:28 +0100, Tim Auton
><tim....@uton.groupSexWithoutTheY> wrote:
>>My point was that population growth (ignoring immigration) is
>>approximately zero in the most developed nations. It's exponential
>>growth with an exponent of 1, if you want to put it that way. In other
>>words: I find the idea that humans will continue to breed and increase
>>the population ad-infinitum, outstripping all available resources,
>>somewhat unlikely.
>
>exponent of `1' doesn't give exponential growth.
I have a horrible feeling you just said that an exponent of n doesn't
give exponential growth, where n was a member of the set of real
numbers. You could make an argument about the sign of "growth" but
unfortunately for you "negative population growth" is a perfectly
valid term. I bet you'd argue that you can't have a negative
acceleration either.
>Also reproduction is
>a natural response to an instinct and all your figgering hasn't got a
>ghost of a chance against inborn nature.
Explain the approximately zero population growth of the most developed
societies. There is ample evidence that the ghost is doing rather
well. It's actually quite easy once you extend your view of resources
beyond the obvious (food etc.). I think you'll find technology has
trumped nature for a couple of centuries. Try looking at human beings
as part of nature and vice-versa.
>If you want to `control' population just turn your back and ignore
>poverty, starvation, disease, and war - then nature can control it
>naturally in the usual manner.
Ahhh, so humans aren't natural. How, exactly?
Sander Vesik
>
> Because exponential growth will always outstrip polynomial growth at some
> any supplies they can reach (cubic polynomial even at the speed of light)
> and are going to have to control their population sooner or later. Why not
> sooner?
I've got news for you - Malthusianism was dead by 1900s, time to
wake up and smell tha air.
> Grim
>
>
--
Sander
+++ Out of cheese error +++
Sander Vesik
> In sci.space.policy Sander Vesik <san...@haldjas.folklore.ee> wrote:
> > In sci.space.policy Ian Stirling <ro...@mauve.demon.co.uk> wrote:
> >> <snip>
> >> > Yes, there is reason. The Oort Cloud of comets go well beyond the
> >> > heliopause.
> >> > The Oort Cloud of comets may extend out to 100,000 AU --- maybe 3 light
> >> > years from the Sun. This is a good fraction of the way to the nearest star.
> >>
> >> It doesn't give you any benefit.
> >> you find it?
> >
> > You would probably find them with radar. Large flimsy structures
> > and all that. Making use of them is of course a different and rather
> > interesting trick.
>
> Radar doesn't really work very well at extreme ranges.
> r^4 is nasty.
yes. but you don't need extreme ranges, just tens of AU.
Sander Vesik
> "Martin 53N 1W" wrote ...
> > Paul F. Dietz wrote:
> >> N:dlzc D:aol T:com (dlzc) wrote:
> >>
> >>> Earth,
> >>
> >> We don't have fusion because building an economical fusion reactor
> >> is simply a difficult problem.
> >
> > Look up ITER:
> > http://www.iter.org/
>
> "to aim at demonstrating steady-state operation using non-inductive current
> drive with a ratio of fusion power to input power for current drive (Q) of at
> least 5."
>
> ... would appear to be one of the most relevant bits. Of course it does say
> "to aim at". And 'economical' is _not_ one of the aims.
Why should it? Its science project, not a fusion startup company.
Sander Vesik
> Dear Paul F. Dietz:
>
> "Paul F. Dietz" <di...@dls.net> wrote in message
> > N:dlzc D:aol T:com (dlzc) wrote:
> >
> > > We have nuclear fusion now. What we cannot do is keep it running on
> Earth,
> > > fission, for the amount of power produced, and scaling up will not much
> > > improve this.
> >
> > This is bullshit. The large number of neutrons produced is not the
> > reason we 'can't keep it running', and fusion is not dirtier than
> fission.
>
> Okay, let's see if I can say this in a more pollitically correct way. The
> very high temperatures require low nearby masses. Since shielding must be
> further away, more volume of it is required. Fusion does produce lots of
> neutrons (on a kg per kg basis), and the first thing neutrons hit is
> structure and "drive"... not shielding. You are right, in that currently,
> containment of the plasma is the hard step. Beyond this, is disposal of
> the works that is bombarded by neutrons, which necessarily located inside
> the shielding.
You are still simply wrong. using say isotopicly pure inner coating
for the conatinment sides, you might not have *any* works to be disposed
of at all. Just replace and recycle the coating.
Isotopicly pure materials are quite common.
>
> David A. Smith
Sander Vesik
> Dear Paul F. Dietz:
>
> "Paul F. Dietz" <di...@dls.net> wrote in message
> > N:dlzc D:aol T:com (dlzc) wrote:
> >
> > >>is still utter bullshit.
> > >
> > >
> > > They were still toying with the idea of using a fusion facility for a
> few
> > > months, then abandoning it until it "cooled down". A nuclear reactor
> > > facility, even a fusion one, cannot be easily hauled off and buried
> > > underground. Will you settle for "may end up being as dirty as
> fission"?
> >
> > No. The quantity of long-lived nuclear waste produced is orders of
> > magnitude less than in a fission reactor of similar capacity.
> >
> > I'll settle for your admission that your original statement was
> completely
> > wrong. Deal?
>
> No deal. Not if you leave an entire "hot" reactor behind... And you had
> to qualify with "long-lived" anyway! ;>)
You should first clarify why you imagine there will be a "hot" reactor.
Sander Vesik
> N:dlzc D:aol T:com (dlzc) wrote:
>
> >>I'll settle for your admission that your original statement was
> >
> > completely
> >
> >>wrong. Deal?
> >
> >
> > No deal. Not if you leave an entire "hot" reactor behind... And you had
> > to qualify with "long-lived" anyway! ;>)
>
> after 10 years is rather relevant, no?
There need not be any (well... maybe grams) of radioactive waste.
>
> Still going to hold out on admitting your original statement was full of shit?
>
> Paul
Sander Vesik
> "Grimble Gromble" <grimble...@virgin.net> wrote in message news:<wctUc.269$A_6...@newsfe2-gui.ntli.net>...
> > > h...@mailmoka.ro (Hex) wrote in message
> > news:<393e5637.04081...@posting.google.com>...
> > ...
> > > In theory, the force of gravity is *infinite* in its reach (F <> 0
> > > until r = infinity),
> > ...
> > That only works in Newtonian gravity where the 'speed' of the gravitational
> > influence is infinite. In General Relativity, the speed is limited to that
> > of light. It can only influence infinitely distant objects if it has an
> > infinte amount of time to do so.
>
> I use *infinite* reach as only a point of notional illustration. If
> the Sun's gravity reaches just half way out to Alpha Centauri (2.2
> light years) then the total gravity coming from Alpha Centauri's two
> principal suns (A and B) with a combined mass of 2.0 x solar mass will
> more than meet us half way.
Sun's gravity reaches out to at least 5 billion lightyears.
Robi
> In sci.space.policy Grimble Gromble wrote:
>>
>> Because exponential growth will always outstrip polynomial growth at some
>> stage, humans (who tend to reproduce exponentially) will inevitably exhaust
>> any supplies they can reach (cubic polynomial even at the speed of light)
>> and are going to have to control their population sooner or later. Why not
>> sooner?
>
> I've got news for you - Malthusianism was dead by 1900s, time to
> wake up and smell tha air.
hehe :) wasn't he the one to be 969 years old? ;o)
--
Robi "Sorry, couldn't resist"
(3.6#@ 3.39 yrs)
vonroach
wrote:
>Jeez, I thought your brand of eugenic racism went out of style in 1945.
>
>BTW, your first paragraphs there are directly contrary to evidence.
>The countries with the high standards of living, peace, and good
>health care have low fertility rates and soon will have declining
>populations. But bigots and misanthropes don't let facts get in
>the way of a good hate-filled spew, do they?
>
> Paul
Did you mistakenly think that my solutions applied to any specific
`race'. That is just your interpretation. The results you cite, if
true, clearly indicate that nature has a correction underway, if we
just don't blunder and disrupt it.
And yes, people who are sincere about a problem do face facts, while
the pious do-gooders always neglect them.
vonroach
<tim....@uton.groupSexWithoutTheY> wrote:
>vonroach <hadr...@earthlink.net> wrote:
>>On Sat, 21 Aug 2004 22:12:28 +0100, Tim Auton
>><tim....@uton.groupSexWithoutTheY> wrote:
>[snip]
>>>My point was that population growth (ignoring immigration) is
>>>approximately zero in the most developed nations. It's exponential
>>>growth with an exponent of 1, if you want to put it that way. In other
>>>words: I find the idea that humans will continue to breed and increase
>>>the population ad-infinitum, outstripping all available resources,
>>>somewhat unlikely.
>>
>> Tim, your figuring is handicapped by some mathematical deficits. An
>>exponent of `1' doesn't give exponential growth.
>
>I have a horrible feeling you just said that an exponent of n doesn't
>give exponential growth, where n was a member of the set of real
>numbers. You could make an argument about the sign of "growth" but
>unfortunately for you "negative population growth" is a perfectly
>valid term. I bet you'd argue that you can't have a negative
>acceleration either.
Your angst is justified. In the expression 1^n, where n can be any
positive or negative integer, what value do you suggest we assign to n
to give an exponential increase or decrease of 1?
>>Also reproduction is
>>a natural response to an instinct and all your figgering hasn't got a
>>ghost of a chance against inborn nature.
>
>Explain the approximately zero population growth of the most developed
>societies. There is ample evidence that the ghost is doing rather
>well. It's actually quite easy once you extend your view of resources
>beyond the obvious (food etc.). I think you'll find technology has
>trumped nature for a couple of centuries. Try looking at human beings
>as part of nature and vice-versa.
Even discounting all the legal murder of babies, the population
continues to grow everywhere. Even genocide, starvation and disease
can not keep it in check in Africa and India. Nature has found
support in improved prenatal and natal care and all the research in
helping many with genetic defects to survive, as well as improved
medical care. Population growth in developed countries is due to
rising live birth rates and rampant immigration. Only communist and
some socialist societies are laggards.
>>If you want to `control' population just turn your back and ignore
>>poverty, starvation, disease, and war - then nature can control it
>>naturally in the usual manner.
>
>Ahhh, so humans aren't natural. How, exactly?
Humans are natural, and that is the subject under discussion. Some
humans just think they are not natural in their hubris.
>
>Tim
vonroach
<san...@haldjas.folklore.ee> wrote:
>I've got news for you - Malthusianism was dead by 1900s, time to
>wake up and smell tha air.
So? Many scientist and thinkers are dead but their ideas live and
still must be examined.
vonroach
<san...@haldjas.folklore.ee> wrote:
>Sun's gravity reaches out to at least 5 billion lightyears.
Theory or measurement?
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"vonroach" <hadr...@earthlink.net> wrote in message
news:1s4ii0d7bvfsvfv3f...@4ax.com...
The Moon's orbit is perturbed by, among other things, asteroids out past
Mars. The line of action of gravitation appears to be instantaneous
between orbitting bodies, so that distance is a non-issue to the effect.
Do you not think it scales? Do you have any reason to believe that
gravitation from the Sun doesn't extend out at least as long as the Sun has
been "accreted"?
David A. Smith
Grimble Gromble
news:10931714...@haldjas.folklore.ee...
Any cult following of Malthus may have died by the 1900s, however his
reasoning was that IF population levels continued to grow geometrically (as
he termed it) whilst resources did not grow correspondingly quickly, then
mankind would become progressively poorer. At the time, this mathematically
precise statement flew in the face of 'popular' economic ideas.
Nevertheless, it is as true today as it was then.
Starvation, as he predicted, is one of the presently functioning limiting
factors preventing exponential growth. Other factors weigh more heavily in
the so-called developed nations. It could well be argued that the desire for
wealth is the driving force behind the reduced growth rates in such
countries. To ignore Malthus because he was a pessimist, or because
'popular' opinion shuns such a bleak outlook (not at all bleak if one
considers that this same view gives one a possible escape from poverty by
ensuring population growth does not remain exponential by using alternative
means than starvation - war if you will, but not a civilised solution in my
opinion), is akin to the Usans continued approach to the energy crisis (what
crisis?).
I've no doubt that some of you out there know a good deal about game theory.
Perhaps you could answer me this. Given a fixed set of resources, and a
reasonable (your choice) method for evaluating quality of life, what
criteria would result in the maximum possible total quality of life? Would
it be everybody equally wealthy ( lots of poor starving people, or a select
overstuffed few, or somewhere in between) or an unequal distribution (some
starving, some well off and the rest in between)?
Grim
Tim Auton
Duh!
Tim Auton
[snip]
>Even discounting all the legal murder of babies, the population
>continues to grow everywhere. Even genocide, starvation and disease
>can not keep it in check in Africa and India. Nature has found
>support in improved prenatal and natal care and all the research in
>helping many with genetic defects to survive, as well as improved
>medical care. Population growth in developed countries is due to
>rising live birth rates and rampant immigration. Only communist and
>some socialist societies are laggards.
Oh dear. First abortion is murder, then a bit of McCarthyism. Plonk.
Rand Simberg
Neither, actually. It's an arbitrary number.
Alan Anderson
It's not arbitrary at all. It's the age of the sun. The distance
specified just assumes (reasonably, IMO) that gravity propagates at the
speed of light.
Rand Simberg
>>>>Sun's gravity reaches out to at least 5 billion lightyears.
>>>
>>>Theory or measurement?
>>
>>Neither, actually. It's an arbitrary number.
>
>
> It's not arbitrary at all. It's the age of the sun. The distance
> specified just assumes (reasonably, IMO) that gravity propagates at the
> speed of light.
You (and Sander) are right. Mea culpa.