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Old April 26th 04, 01:40 AM
Pat Flannery
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Default Seasons on gas giant moons

Sander Vesik wrote:

Well.. would it really be all that different from our moon (which is much
more active in beliefs than mere planets) except there would be more of
them and on different schedules?

Assuming we are both talking about other moons viewed from an inhabited
one in orbit around a gas giant, there would be a major difference- our
Moon undergoes phases and an occasional eclipse, but it stays the same
size in the sky (although it still looks bigger to me when it's on the
horizon...I know it's not... but it looks bigger anyway); but the moons
in orbit near the inhabited one would appear in the sky as bright stars
when they are far away, but become visible discs like the Moon as they
drew close to the inhabited one in their orbits.
The planets in our solar system vary in position and brightness to the
naked eye, but the only two things that can be seen as discs in our sky
(the Sun and Moon) stay the same apparent size all the time (the Moon
varies a bit, but probably not enough to be very noticeable).
Now put yourself in the position of an observer on our hypothetical
inhabited moon- the sky is a very complex place; assuming that your
planet is tidally locked, then on one side of the moon, you've got the
big gas giant hanging pretty much motionless in the sky, but changing
its phases as you orbit around it; given it's size, you probably get
very frequent eclipses of your system's sun; but there are two other
groups of odd objects in the sky- the other moons of your gas giant, and
the other planets in your solar system. The moons inboard of you
probably cross in front of the gas giant quite often, and their shadows
can be seen falling on the gas giant; in fact _your_ moon's shadow can
probably be seen falling on the gas giant- and once you make the
connection between _that_ shadow and the ones the other moons are
casting, the realization sinks in that those discs in the sky are worlds
like the one you are living on. Then there are the other star-like
moving objects to contend with- the star's other planet; their motion is
noticeably different from the moons, and this soon would also start
speculation as to what they were.
Remember the contortions that philosophers went through in an attempt to
make a geocentric cosmos work? Those would look simple compared to what
one would have to go through to make a moon-centered one work! You'd end
up with something with as many layers as a onion hooked together in
incredibly convoluted ways- the whole thing would be so complex to even
try that I'd bet that it never would be even seriously considered before
the correct sun-centered view arose.



case, based on the apparent reduction in size of people seen at a distance.
A hypothetical civilization on such a planet might have a fairly
accurate idea of true cosmology at a far earlier stage of its evolution
than any Earth civilization did. Imagine nomadic hunter-gatherers with
a understanding of a sun-centered universe with multiple worlds... is
one of the other moons where you go when you die?



I'm not certain that would happen, or at least happen considerably earlier
than on Earth (where it didn't really happen all that late either). But
yes, going to another Moon when you die sounds liek a reasonable guess.

I'll bet they would probably think that all the other moons had life on
them of one sort or another.

Pat