A few hundred years ago most people in the western world who were capable
of discussing how they thought the universe was organized would have
probably said something about the Earth, heaven and hell. (It is surprising
how many people still think in these terms.) Without regard to any
practical benefits, Copernicus, Bruno, Galileo, Newton and others taught us
that was not the way the universe was. Using that information, and
encouraged by military objectives and very large budgets, we engineers
learned how to make machines that could go into cis-lunar space, and we are
now considering details of how to profit from doing that. I think this is
good, but I don't think it reflects well on us to forget that it was science
that made it possible. Science is necessary, though not sufficient.
Engineering is also needed, of course.
The idea of finding all NEA's larger than some particular value ignores
the current science on those objects. They end their existence mostly by
colliding with planets, and we are at some risk from such collisions. But
new NEA's continue to be made, they must be being made, otherwise there
would not be any left after nearly 5 billion years of the Solar System's
existence.
NEA's are made from collisions and gravitational perturbations of main
belt asteroids, and also from comets being nudged in from the Oort cloud and
Kuiper belt. The Tunguska event of 1908 was most likely caused by a small
comet coming down over Siberia, not an NEA. One of the reasons we need to
colonize space is that all humans on Earth could die from a single collision
with an NEA or comet, and that would set our science, engineering,
languages, religions, etc., as well as our population, back to zero. So
this is a serious topic, in fact it is hard to imagine any topic more
important than this. I am glad is also so much fun.
Happy weekend, Jay S. Huebner at jhuebn@...
It is true that the population of NEOs 100m and larger will increase and
decrease due to gravitational perturbations of Jupiter, and due to other
effects. But it's not as though those populations are rapidly fluctuating
by the hour. A network of ground-based and space-based telescopes doing
automated sky searches could find all NEOs larger than 100m, all that
currently exist. Such a network would also uncover plenty of other
interesting objects such as smaller NEOs, comets (long- and short-period),
Centaurs, and TNOs. And such a network could monitor any changes in the
NEO population, should there happen to be any increase or decrease in the
short-term.
would NOT remove all threat to Earth of collision by big objects. Not by
a long shot. Finding all comets that could potentially enter the inner
solar system is a much bigger nut to crack than finding all 100+ meter
NEOs. We have to start with baby steps. And finding NEOs is a
particularly useful activity anyway for space industrialization reasons.
I have nothing against science per se. But I feel that NASA is
essentially a zero-sum game. If they're spending money on probes to
Mercury/Pluto/Europa/Mars, then that means they're not spending money on
probes to NEOs and Luna. Given that environment, I look very skeptically
on such expenditures. When a probe eventually returns pictures from
Mercury, I personally will eagerly surf the project Website and look at the
pretty pictures and factoids. But I will also mourn the opportunities
lost by spending money on Mercury that should have been spent on NEOs and
Luna. It's an opportunity cost thing, that's all. And ISS is of course
a much bigger hog of funds than all of the misguided planetary probes put
together.
Have a good weekend.
Ron Menich
"Huebner,
06/08/01
03:41 PM
Please
respond to
ssi_list
A few hundred years ago most people in the western world who were
capable
of discussing how they thought the universe was organized would have
probably said something about the Earth, heaven and hell. (It is
surprising
how many people still think in these terms.) Without regard to any
practical benefits, Copernicus, Bruno, Galileo, Newton and others taught us
that was not the way the universe was. Using that information, and
encouraged by military objectives and very large budgets, we engineers
learned how to make machines that could go into cis-lunar space, and we are
now considering details of how to profit from doing that. I think this is
good, but I don't think it reflects well on us to forget that it was
science
that made it possible. Science is necessary, though not sufficient.
Engineering is also needed, of course.
The idea of finding all NEA's larger than some particular value ignores
the current science on those objects. They end their existence mostly by
colliding with planets, and we are at some risk from such collisions. But
new NEA's continue to be made, they must be being made, otherwise there
would not be any left after nearly 5 billion years of the Solar System's
existence.
NEA's are made from collisions and gravitational perturbations of main
belt asteroids, and also from comets being nudged in from the Oort cloud
and
Kuiper belt. The Tunguska event of 1908 was most likely caused by a small
comet coming down over Siberia, not an NEA. One of the reasons we need to
colonize space is that all humans on Earth could die from a single
collision
with an NEA or comet, and that would set our science, engineering,
languages, religions, etc., as well as our population, back to zero. So
this is a serious topic, in fact it is hard to imagine any topic more
important than this. I am glad is also so much fun.
Happy weekend, Jay S. Huebner at jhuebn@...
> One of the reasons we need to
> colonize space is that all humans on Earth could die from a single
collision
> with an NEA or comet, and that would set our science, engineering,
> languages, religions, etc., as well as our population, back to zero.
as this.
For example, several months will be available to prepare for a
conjectured collision with a Hale-Bopp type of object. For just one
of many possible courses of action, the United States might "bury"
equipment and components necessary for self-sufficient living in
several unmanned sites well protected to survive the after effects of
an impact. About ten thousand of the "best and brightest" (with, of
course, those making the final decisions included in this mix) could
then board the Navy's nuclear powered submarine fleet and transit to
that global sea location that would be the least effected by the
blast. As has been demonstrated many times in the past, such a
contingent could easily remain submerged for ten weeks, at which time
all short-term effects would have played their course. The submarines
would then surface and the occupants would establish a new foothold
for the human race from the locations previously prepared for this
purpose. They could use the submarine reactors for many, many years
of electrical support in their survival efforts.
But it would be nice to have a supplementary survival mechanism in
place above the Earth's gravity well. A Stanford Torus and/or a
Bernal Sphere would fill this need nicely.
Best regards,
Leon Neihouse
http://www.alphaspaceproducts.com
>>>>But it would be nice to have a supplementary survival mechanism in
place above the Earth's gravity well. A Stanford Torus and/or a
Bernal Sphere would fill this need nicely.>>>>
would prevent the damn thing from hitting us in the first place. For
threatening comets, we could use a cascading system. A modest nuclear
device would be exploded within a 100m diameter NEO. The NEO would be
deflected onto a collision course with the comet. A mass driver would make
minor course corrections after the bomb was exploded. A system such as
this, would give us the ability of leveraging the power of our nuclear
explosives. Alternatively, with a powerful mass driver, equipped with a
large nuclear power source, the asteroid could be placed on a collision
course without the use of a bomb. This could be achieved after about 3
months of thrusting.
Tony
Comets with bright tails that we can see months before impact are only one
class of potential impactors. We could be impacted by an asteroid or
burnt-out comet that has no tail. We could get hit without seeing it
coming, or perhaps detecting it only at the last minute.
"Leon
06/12/01
10:31 AM
Please
respond to
ssi_list
> One of the reasons we need to
> colonize space is that all humans on Earth could die from a single
collision
> with an NEA or comet, and that would set our science, engineering,
> languages, religions, etc., as well as our population, back to zero.
I agree with this general sentiment but I doubt that it is as extreme
as this.
For example, several months will be available to prepare for a
conjectured collision with a Hale-Bopp type of object. For just one
of many possible courses of action, the United States might "bury"
equipment and components necessary for self-sufficient living in
several unmanned sites well protected to survive the after effects of
an impact. About ten thousand of the "best and brightest" (with, of
course, those making the final decisions included in this mix) could
then board the Navy's nuclear powered submarine fleet and transit to
that global sea location that would be the least effected by the
blast. As has been demonstrated many times in the past, such a
contingent could easily remain submerged for ten weeks, at which time
all short-term effects would have played their course. The submarines
would then surface and the occupants would establish a new foothold
for the human race from the locations previously prepared for this
purpose. They could use the submarine reactors for many, many years
of electrical support in their survival efforts.
But it would be nice to have a supplementary survival mechanism in
place above the Earth's gravity well. A Stanford Torus and/or a
Bernal Sphere would fill this need nicely.
Best regards,
Leon Neihouse
http://www.alphaspaceproducts.com
>>>Alternatively, with a powerful mass driver, equipped with a
large nuclear power source, the asteroid could be placed on a collision
course without the use of a bomb. This could be achieved after about 3
months of thrusting.>>>
thousands, and set up the mission that would be required in order to
deflect it, I suppose that this method would only work if the asteroid or
comet were discovered at least 18 months before impact.
Tony