Sedna, space probes?, colonies? what's next?

Dick Morris wrote:


Rand Simberg wrote:

On Thu, 18 Mar 2004 18:00:20 GMT, in a place far, far away, Dick
Morris made the phosphor on my monitor
glow in such a way as to indicate that:

Debatable.
Stick copies of biosphere II all over the world, and you end up with
well over 10 times the population.

How much did Biosphere II cost, per inhabitant?

A lot, but you can't conclude anything from that, since there were no
economies of scale.

Biosphere II wouldn't be a very good model in any event, since it's
primary use is scientific research. It's far from an optimum approach
for growing food.

True.
But, it's a minimum number.
For a first attempt, that seems likely to be adequate in area at least,
it gives a ballpark number.
You wouldn't copy it of course.

Henry Spencer wrote:
In article ,
G EddieA95 wrote:
If Earth is not to become a pre-techological subsistence park, it will *have*
to be solar one day.

Or fusion. Or some form of imported energy (antimatter manufactured down
near the Sun?).

Mercury might well provide an interesting platform for energy generation.


Even for solar, there's no reason why solar power for Earth has to be done
with solar collectors on Earth's surface -- in fact, that's easily the
*worst* place in Earth's vicinity for collecting solar power.

Possibly, but we aren't even trying to do that particularily hard, which
has implications for investment in any non-traditional source whetever on
earth or otherwise.

Also tens of thousans of square kilometers where clouds never appear
easily exists and are available on earth. They are just remote from
consumers. And energy transport problems from there are much less than
for anything orbital.

--
Sander

+++ Out of cheese error +++

Mike Combs wrote:
"Sander Vesik" wrote in message
...

I think there is a slight difference between 'can be done' and 'makes
sense to do' -

Oh, total agreement here. I was only trying to make the point that whatever
other objections might be raised, an inability to use solar power needn't be
one of them.

Personally, I can't see a reason for anybody to want to live at 10x the
distance of Pluto... unless they REALLY hate people.

Well, even the distance of Pluto should be really confortably empty and
uninhabited for at least several hundreds of years. Even with easily
available really advanced nanotech and FTL.

But relatively speaking, the people who went into Australia or the west of US
did go as far as Moon/Mars/Pluto - just pick a commonly available spaceship
speed. ;-)


given the distance, does it even make sense as a space
based source of ice/water?

There are surely lots of others between here and there.


Yes - but the majority of mass of OOrt cloud may well be even further away
than Sedna.


--


Regards,
Mike Combs
----------------------------------------------------------------------
We should ask, critically and with appeal to the numbers, whether the
best site for a growing advancing industrial society is Earth, the
Moon, Mars, some other planet, or somewhere else entirely.
Surprisingly, the answer will be inescapable - the best site is
"somewhere else entirely."

Gerard O'Neill - "The High Frontier"

--
Sander

+++ Out of cheese error +++

In article ,
G EddieA95 wrote:
*have* to be solar one day.
Or fusion. Or some form of imported energy (antimatter manufactured down
near the Sun?).

Manmade fusion doesn't exist yet...

Not in the form of power plants, you mean. (Manmade fusion was achieved
on a tiny scale in high-energy physics labs in the 1930s, and on a rather
larger scale at Eniwetok Atoll in 1952.)

Even in power plants, here is every reason to think it *will* exist, given
adequate time and effort. It may not be the most convenient form of power
in several ways, but it's almost certainly feasible, and the fuel supply
is very large.

and antimatter is an energy *sink*
(making it requires more energy than you get from it).

Note what I said: "imported energy". Antimatter is a way of shipping
energy around in a very concentrated form. So far as we know, there is no
natural supply of it, so it would have to be made elsewhere, from some
other form of energy. That's still potentially an interesting approach in
the long run.

Even for solar, there's no reason why solar power for Earth has to be done
with solar collectors on Earth's surface -- in fact, that's easily the
*worst* place in Earth's vicinity for collecting solar power.

Worst, yeah, but with current space technology, by far the cheapest.

The time frame specified was "one day". The costs of current space
technology are irrelevant.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

G EddieA95 wrote:
If Earth is not to become a pre-techological subsistence park, it will
*have*
to be solar one day.

Or fusion. Or some form of imported energy (antimatter manufactured down
near the Sun?).

Manmade fusion doesn't exist yet, and antimatter is an energy *sink* (making it
requires more energy than you get from it).

It being a sink is hardly suprising - all presently used forms of transporting
energy are, some very trasticly so. Antimatter is just a compact way of transporting
energy - whetever it actually becomes economical at some point is a different
question (you'd have to compare a antimatter based source to say a fusion reactor
and its supply of fuel).

--
Sander

+++ Out of cheese error +++

On Thu, 18 Mar 2004 22:27:05 GMT, h (Rand
Simberg) wrote, in part:

There is room for plenty more people without having to totally
eliminate habitat, and the planet's "net photosynthetic product"
(whatever that means) is not a fixed number.

This is valid. One could certainly fill the Sahara with hydroponic
greenhouses.

However, while on Mars, a habitat has no *economic competition* for
producing food, this is not true on Earth. Chopping up Earth's last
wildlife habitats for agricultural land is *cheaper* than increasing
Earth's agricultural production artificially - and, thus, the survival
of wildlife habitat in an Earth more populous than today's would
require immense amounts of self-discipline and law enforcement.

Without massive redistribution of wealth, large sections of the
Earth's population would lack the inclination to make this kind of
effort.

Incidentally, my second paragraph above also explains part of why we
want to colonize Mars first instead of colonizing Antarctica.

John Savard
http://home.ecn.ab.ca/~jsavard/index.html

On Sat, 20 Mar 2004 00:00:10 GMT, in a place far, far away,
lid (John Savard) made the phosphor on
my monitor glow in such a way as to indicate that:

If humanity has any value, then twice as much has twice the value. If
humanity doesn't have any value to you, then do you propose that we
exterminate ourselves?

If it becomes possible to support additional humans in comfort and
peace and happiness, then I am for it.

That is clearly possible. Or at least as "clearly" as your next
proposition.

Right *now*, however, there is
a great amount of poverty, even in the wealthiest nations. Clearly,
our population is much larger than can be effectively accomodated on
Earth with our present technological level.

That is not clear at all. Your conclusion doesn't follow from your
premise.

Poverty is largely caused by misgovernment, not by overpopulation per
se, even at our current technology level.

What is so nonaesthetic about the Jupiter system?

No, that was not my meaning. The aesthetic concern would be with
disturbing the pristine beauty of well-known Solar System bodies
instead of obscure asteroids.

So to your mind, we should not go to the moon, or Mars either, for aesthetic
reasons?

Such reasons are IMO misplaced. Any other Sol System body will have radiation
requiring human life to be underground. Except for landing craft and surface
halftracks, no change to any of them will be visible from space.

If Earth is not to become a pre-techological subsistence park, it will
*have*
to be solar one day.

The population will have to be much smaller for both conditions to be
fulfilled.

The population will go down if Earth goes to subsistence. If don't agree that
it will have to go down otherwise. And aren't you afraid of the necessary
*means* of getting it down?

Solar can make the world work, especially if efficiencies improve.


Also, our deuterium is not going to run out nearly as fast as the oi

Only because we presently can't use it.

*cheaper* than increasing
Earth's agricultural production artificially - and, thus, the survival
of wildlife habitat in an Earth more populous than today's would
require immense amounts of self-discipline and law enforcement.

And lowering the human population won't?

I sure hope that the happiness of wildlife species is to you worth the
Chinese-type atrocities that a population-control society will impose on a
global scale. It certainly isn't to me.