RE: OT-Stars and planets and such

G'day again,

>I would like a answer to this as well. 
>I remember from some of my sci-fi
>novels, a area of habitablity is a
>certain distance from each star, and
>the hotter the star, the further away 
>the habital zone is. For dim stars,
>the habital zone is too close, and 
>a planet will become tidelocked to the
>star, meaning a habitable biospere would 
>be imposible. 

Well I don't claim to be an astrobiologist, but at least within my
circles
and the papers I've read on the subject this is still a matter of very
great
debate. Experimental work and a good number of thought experiments
suggest
that tide locked worlds may be just great for life as they're so damn
constant. Think about it on Earth we have fluctuating day length,
fluctuating levels of radiation, fluctuating water levels (due to
tides),
fluctuating seasons and climate on very short (daily) and immensely long
(millions of years) scales. Everything fluctuates for heavens sake!! Now
while fluctuation (at least in the last few billion years) obviusly
hasn't
been all bad for the kind of life on this planet its actually much
easier to
get simple life to flourish under constant conditions (look at all the
labs
around the world who go for constant conditions to keep things going).
There's nothing more constant than a tide locked planet ;)

Best article I saw on this was a year or so ago where a scientist was
arguing that maybe we're looking in all the wrong spots for life -
because
we're at 1AU around a G star we assume other life will be too (not a bad
empirical assumption mind). However, put yourself in the mind of a being
from a K star on a tidally locked world. Why the heck would you bother
looking for life around G class stars? Any habitable planets would have
to
be so far out due to the higher levels of radiation that they couldn't
be
tide locked, so you get varying light levels and water levels (even
without
the moon there would be some tides) just to name a few hazards. What
kind of
life could live under such varying conditions? Heavens it'd have to be
really simple to cope, nothing too complex would ever be able to deal
with
that much variation in radiation and biogeochemical media...

Thus with everything we only know a little bit about there's plenty of
room
to let the mind run reasonably free on this one. So far the list of
"possible sites" runs to at least the following (though some are more
marginal than others):

- Terran like rocky planets
- Moons around giant planets (be they rock or gas) 
- Tide locked planets 
- Rogue planets (ones not tied to a solar system). Note these guys are
largely theoretcial I think, some one will surely correct me, but they
could
support life as long as they had enough energy caught up in their
atmospheres, like a semi-self sustaining dynamo. OK its doubtful they'd
ever
evolve biomes etc, but given the time span of the games/histroy we're
considering you could plonk a "fully sealed" station/colony on one for
your
purposes (they're unlikely to need to last for billions of years after
all)

As evidenced by the rogue planet stuff you don't even need to be solidly
in
the habitable zone, but it helps at least ;)
It has as much to do with what you base the ecology on. If you're
willing to
step away from the notion that life HAS to be powered by solar energy
then
the universe is your oyster so to speak. The vent communities and
extremophile populations on Earth show that you can get along just fine
without ever needing solar radiation (it may even be how life got its
kick
off on Earth... and my apologies to any who don't believe in evolution
here,
I'm not trying to being insulting so just ignore the last bit if it
offends
you).

Sorry this turned out so long!

Beth