As far as we know, life only exists on our planet (in the whole universe). I disagree with this notion in general, because of the astronomical size (no pun intended) of the universe.

If we're accepting the fact that life can form elsewhere (as I am for the sake of this thread, and in general), I've got a few questions. They're majoratively personal opinion questions, so I don't expect "Correct" or "incorrect" answers.

Life can form on planets, this we know. Theoretically, life can form on moons. If life was to be found on a moon, say Europa (microbial), this would prove that life could form on moons rather than just planets.

What repercussions do you believe this would have? (Both political, social and Religious) If the life wasn't microbial (Fish, for instance) same question.

This would result in a great change in the believed "Habitable" zone for life considerably. Might it even mean that life could exist on a Rouge Planet system (or around a brown dwarf)? With the heat used for life being generated through Geothermal Tidal forces?

Asimov (not only a sci-fi writer but a biochemistry professor) wrote an essay in the 60s outlining posible biochemistrys for life on ALL the planets of the solar system.... so the thought is not new.

Moon or planet... why would that matter?? Life is life is life.

Just finding a different ecology of lifeforms ANYWHERE would be the big news, not the details themselves....

You're missing the point though. A planet like Europa gets the majority of its energy from geothermal energy generated as a result of tidal forces from orbiting its parent, unless I'm mistaken.

This means that if life were to exist on such a planet, life might exist around any type of star (almost any), not just in the habitable zone around main sequence.

Life could even survive on moons of planets wandering in deep space according to David Stevenson, who wrote a paper called "Possibility of Life Sustaining Planets in Interstellar Space"
see
http://en.wikipedia.org/wiki/Rogue_planet

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Well, I'm working on a storyline that has several races evolving on terrestrial moons of gas giants. There are many things to take into consideration. Tidal heating is one source of heat, but it would result in a Europa scenario if it's well outside the habital zone of the star. I put mine near Mars orbit so that it has both solar warmth as well as geological processes to avoid the freeze-up that happened on Mars.

Radiation protection can be made by the gas giant, or the moon itself but the gas giant may have a major radiation flux zone, such as happens with Jupiter and Io and to a lesser extent, Europa. I think you'd need a thick atmosphere to help protect against that flux, a significant magnetosphere or local magnetic fields on the moon or a gas giant that does not have such a high flux (I'm not sure if all gas giants must have this or not, perhaps Jupiter is special in this regard). You could also have a flux and then have organisms that either survive it or thrive upon it as a source of energy.

Your moon will probably be tidally locked, so it will have long days and nights. One of my life-bearing moons in my story orbits every 100 hours, making day and night both about two earth days long. However, the gas giant reflects a lot of light back onto the moon at night preventing significant cooling on the near side. The far side has more extremes in temperature because it is the only part that experiences real night. However, the near side does experience a 3 hour eclipse of the sun every local day at noon.

The organisms will need to adjust do your scenario, but gravity, atmosphere and water availability will probably drive evolution more than the solar cycle, so long as there is enough light to work with.

My aliens developed society slowly and had a non-contentious culture due to geography preventing disparate cultures from developing. They all had the same basic astronomy based religion with the sun, mother planet, and sister moons, and the couple other planets that were occasionally visible. They didn't discover stars until they ventured to the far side where it got dark enough to view them since the near side was always well illuminated (the daily noon eclipse was complete and they did get occasional hints of stars, weather permitting, but lots of light was still refracted through the gas giant's upper atmosphere and reflected off its orbital rings).

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"What you think you thought you saw you did not see." Agent J, MiB - Manhatten Bureau

No, the HZ only relates to planets with Earthlike surface conditions and atmosphere.

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"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

In astronomical terms, yes. In terms of actual habitability, per the OP, not really. I've read that Venus would be habitable if it had an earth-like geology and geophysics. The same might be true of Mars.

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"What you think you thought you saw you did not see." Agent J, MiB - Manhatten Bureau

An Earth-like geology requires active plate tectonics. I remember reading somewhere that liquid water was required for plate tectonics.

If it would be too hot on venus for liquid water to form (in relative abundance) under primordial circumstances, plate tectonics freezes up and you have modern day venus.

So, Liquid water would play an extremely large role in the formation of life, not just required for life itself, but also required for the circumstance that begin life to come around.

Yes, but the slow spin of Venus and/or lack of a magnetosphere allowed the primordia water to disappear, IIRC.

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"What you think you thought you saw you did not see." Agent J, MiB - Manhatten Bureau

Not having a magnetosphere is a result no plate tectonics, at least, that's what I thought...

And quite frankly, I don't know what venus' slow rotation is caused by, although I imagine maybe a large-impact a very long time ago...

The prevailing theory is that Venus used to rotate faster and in the normal direction, but Solar tidal effects on the massively dense atmosphere pulled the planet to a stop, then slightly to retrograde.

__________________
"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

I thought the collision theory was at the forefront or at least equal footing...

Not that I've heard. But I'm no expert.

Of course, it could just be a case of "tastes great/less filling". An impact could have slowed it partially, and the atmosphere drag did the rest.

__________________
"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

But that presents somewhat of a chicken-egg problem. For the sun to alter to rotation of Venus via tides on the atmosphere presupposes the atmosphere was already there. So, if the loss or lack of a magnetosphere caused the loss of liquid surface water, it must have been unrelated to the planet's rotation. Or maybe the atmosphere was even more massive long ago with lots of water vapor due to heating from the younger, hotter sun and/or geology.

Hmmm, maybe I just answered my own question. Perhaps the atmosphere was just too massive, and when the water vapor was dissociated and blown off after the planetary dynamo/magnetosphere, the planet's effective diameter shrank, and the smaller diameter started moving faster (in the direction of the tide's momentum) like a skater pulling in her arms. Does that make sense?

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"What you think you thought you saw you did not see." Agent J, MiB - Manhatten Bureau

The lack of magnetosphere has only a tiny effect on atmosphere loss. For something the mass of Venus' atmosphere, it's far too small to disperse enough to make much difference.

__________________
"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

There's a great deal of concern about this in the "fundamentalist" type groups. An announcement of aliens would be seen as an annoucement of demons coming in guise of being something else and they would begin to expect their favorite End Of The World scenario, with the person welcoming them (or the nation most welcoming to them) being seen as the Antichrist/Mystery Babylon.

Yes, really.

There's a great suspicion that the various UFO sightings are getting people prepared to accept these demons-in-the-guise-of-aliens.

Which fundamentalist "type" groups? I live in an area thick with Bible-thumping fundies, and I've never heard that one.

__________________
"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

Well, that's a matter of interpretation.

http://adsabs.harvard.edu/abs/2007Natur.450..650B
http://adsabs.harvard.edu/abs/2007Natur.450..629S

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"What you think you thought you saw you did not see." Agent J, MiB - Manhatten Bureau