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

No way, according to James Osberg,
Sedna and Pluto are in opposition,
ie opposite sides of the solar system.


Rats. I was not aware of where the two were in their orbits. Thanks for the
info.

lid (John Savard) wrote in
:
But Pluto - or *even* Sedna - does have one thing going for it. Unlike
Mars, it probably has lots of nitrogen in addition to carbon,
hydrogen, and, maybe, oxygen. And it doesn't have the deep gravity
well of a gas giant. So one could imagine a sustainable society
deriving solar energy from large mirrors out there.

You are advocating *SOLAR* power, out that far?

Lets see. To get the same level of power that 1 square meter of solar panel
on Earth get, you would need to supply about 8300 square meters.

At that range, the sun radiates about the same power as any given 15-degree
circle of starry nightsky.

You dont need large mirrors, you need un-be-fooking-lievably giganic
hugenourmous mudderfookahs of mirrors.

"Marvin" wrote in message
...

You are advocating *SOLAR* power, out that far?

snip

You dont need large mirrors, you need un-be-fooking-lievably giganic
hugenourmous mudderfookahs of mirrors.

All very true. But in 0-G, the mirrors needn't be anything more substantial
than aluminized mylar stretched over bailing wire.

Gerard O'Neill got curious how far a space habitat could range from the sun
simply by increasing mirror size. He decided a good stopping point was when
the mirror came to mass as much as the rest of the habitat. The calculation
came out as 10x the distance of Pluto.

I just read that Sedna is currently about 3x the distance of Pluto (yes, I
know, it gets out a lot farther).

--


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"

"Tamas Feher" wrote in message
...

I don't get all the fuss about travel to Mars and Moon, casue what we need
is another Earth.

Perhaps instead what we need is to give up on the idea of planets entirely.

--


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"

"Greg D. Moore \(Strider\)" wrote:

"Tamas Feher" wrote in message
...
all those planets are potential colonies for future colonists.

No planet or other celestial body is inhabitable by homo sapiens sapiens,
unless it has gravity between 80% to 120% of Earth. Gravity is the most
fundamental force in the Universe and lack of enough gravity (less than
0.8G) depletes your bones and muscles, prevents successful reproduction
and
fetus formation. To much and you are flat.

And where exactly did you come up with those numbers?

The fact of the matter is we don't know for sure. We simply know that 1G is
good, 0G is not so great, and know nothing about in between.

It may be .6 G is enough... maybe not.

We don't even know if pregnancy will work in 0G.
Research has been done at high G (centrifuges, with animals living their
whole lives at multiple G (chikens get real meaty legs)) and 0.999G at the
tops of mountains, but there is little data below that.

There may be a "magic" G level at which everything works OK.
It's be nice if this was under 1/6th G, to allow moon colonies.

It may be rather more complex and the G needed varies with age (up to
18 or so) and for some of it a few hours a day at higher G will be needed.

Confining pregnant women in centrifuges, even rather large ones is
technically possible.
Interesting questions arise about inner ear development in a centrifuge.

We need some testing on animals.

Testing at under .999 or so G is hard, as you've got to go into space
to do it.
To do true tests of gravity fields, you've actually got to go to other
celestial bodies.
However, big centrifuges will probably do OK.

In article ,
"Uddo Graaf" wrote:

Colonies that far away from the Sun? Unlikely. Mankind can multiply like
rabbits and it would still take at least 300 years to fill up the inner
planets and moons. Sedna or its denizen's aren't likely candidates for
colonization and when they are, mankind will probably have developed FTL
(faster than light) propulsion and reach for planets beyond our solar
system.

Unless, of course, FTL travel is impossible.

,------------------------------------------------------------------.
| Joseph J. Strout Check out the Mac Web Directory: |
| http://www.macwebdir.com |
`------------------------------------------------------------------'

Hobbs aka McDaniel wrote:
(TKalbfus) wrote in message ...
I find it interesting that Sedna was discovered near its closest point in its
10,500 year orbit around the Sun. What are the chances of that happening? If
you only consider the planet Sedna, the chances of discovering it while it is
near is closest point to the Sun are very small. Sedna spends most of its time
further away, this leads to the question how many other "Sedna's" are there?
What if we looked for a 10th planet 1000 years ago with the same technology we
have today? Would we find another Sedna-like planet nearing its closest point
to the sun. Sedna will spend 150 closer to the Sun than from where we
discovered it. statistically this leaves room for about 60 planets in 10,000
year orbits around the sun. all those planets are potential colonies for future
colonists. The ones further away will be harder to find, but I'm sure we can
eventually discover them.

We haven't even colonized the moon outside of sci-fi so it's a bit
premature to view Sedna as some kind of development property
Probably will be visited by robot probes within 30 years.

I find this slightly unlikely. 'We'[1] have a terribly bad track history
with deep space probes. I think things have gone very well if there is
a dedicated projec to track and discover Oort cloud objects in teh next
30 years, but sending a probe is IMHO being slightly too optimistic.


-McDaniel

--
Sander

+++ Out of cheese error +++

Mike Combs wrote:
"Marvin" wrote in message
...

You are advocating *SOLAR* power, out that far?

snip

You dont need large mirrors, you need un-be-fooking-lievably giganic
hugenourmous mudderfookahs of mirrors.

All very true. But in 0-G, the mirrors needn't be anything more substantial
than aluminized mylar stretched over bailing wire.

Gerard O'Neill got curious how far a space habitat could range from the sun
simply by increasing mirror size. He decided a good stopping point was when
the mirror came to mass as much as the rest of the habitat. The calculation
came out as 10x the distance of Pluto.

I just read that Sedna is currently about 3x the distance of Pluto (yes, I
know, it gets out a lot farther).

I think there is a slight difference between 'can be done' and 'makes
sense to do' - given the distance, does it even make sense as a space
based source of ice/water?


--


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 +++

"Mike Combs" wrote in message ...
"Marvin" wrote in message
...

You are advocating *SOLAR* power, out that far?

snip

You dont need large mirrors, you need un-be-fooking-lievably giganic
hugenourmous mudderfookahs of mirrors.

All very true. But in 0-G, the mirrors needn't be anything more substantial
than aluminized mylar stretched over bailing wire.

Gerard O'Neill got curious how far a space habitat could range from the sun
simply by increasing mirror size. He decided a good stopping point was when
the mirror came to mass as much as the rest of the habitat. The calculation
came out as 10x the distance of Pluto.

I just read that Sedna is currently about 3x the distance of Pluto (yes, I
know, it gets out a lot farther).

Theres nothing wrong with nuclear. By the time we start considering
space habitats this far out, nuclear fusion might even be viable, but
we can build molten salt fission plants now for fueling a huge colony
for at least a couple of centuries.

Uddo Graaf wrote:

"TKalbfus" wrote in message
...
I find it interesting that Sedna was discovered near its closest point in
its
10,500 year orbit around the Sun. What are the chances of that happening?
If
you only consider the planet Sedna, the chances of discovering it while it
is
near is closest point to the Sun are very small. Sedna spends most of its
time
further away, this leads to the question how many other "Sedna's" are
there?
What if we looked for a 10th planet 1000 years ago with the same
technology we
have today? Would we find another Sedna-like planet nearing its closest
point
to the sun. Sedna will spend 150 closer to the Sun than from where we
discovered it. statistically this leaves room for about 60 planets in
10,000
year orbits around the sun. all those planets are potential colonies for
future
colonists. The ones further away will be harder to find, but I'm sure we
can
eventually discover them.

Colonies that far away from the Sun? Unlikely. Mankind can multiply like
rabbits and it would still take at least 300 years to fill up the inner
planets and moons. Sedna or its denizen's aren't likely candidates for
colonization and when they are, mankind will probably have developed FTL
(faster than light) propulsion and reach for planets beyond our solar
system.


Even with FTL, colonising Oort cloud may be easier than plants around
far-away stars. At 4c it still takes 9months for a one-way trip to
Alpha Cenaturi - and much longer for other stars. FTL - unless it
is high multiples of lightspeed - only makes interstellar travel and
colonisation slightly easier. You will pobably still need generation
ships - just the number of generations born on-ship will be lower.

--
Sander

+++ Out of cheese error +++