[Flipside]

Exactly, and if life on Earth did develop in the 'Pea Soup' environment that most geologist suspect existed at that time, our atmosphere was almost as thick and nearly as poisonous to humans as Venus at the time that life first started here. Much like a deep-sea vent, in fact.
I think that the question has been raised before as to whether Venus is, in fact, a pre-life body?

Oh, and Kara, apparently there are suspicions of Deca-mile deep chasms in the surface of Mercury, possibly down to the mantle caused by heat splitting

[StratComm]

Kara, without an atmosphere, you're either being hit with solar radiation or you aren't.  The surface will transmit some heat as well, but the deliniation between hot and cold is pretty fixed, and very narrow.  Subsurface life, maybe, but the likelyhood of life developing in dry, solid rock (dry in any chemical form, not just H2O) is very low.  The moon has issues with that, and it's in the same radiation exposure level as Earth.  We're pretty much in agreement about everything but terminology though, if you'll read the rest of my last post.

With Jupiter, it's so close to being a small brown dwarf that it isn't even funny.  I still think that most of the superjovian planets being spotted right now will actually be reclassed sooner or later to small stars.

EDIT: Energy in a solar system ultimately comes from one of two places: a star, or the remenants of the system's formation.  Geothermal energy on our rock would have long ago been exhausted if we didn't recieve heat from our star, and even then it's going to run out of heat sooner or later.  Radioactive materials can prolong the life of geothermal activity, but it's a fixed length process.  Add to the fact that geothermal activity has a nasty tendency to start and stop in most situations where it can occur, and it makes life that much more difficult to harness.  Black smokers tend to be a bit more fixed, but they have the drawback of requiring a liquid medium to keep the geothermal energy concentrated and harnessable, and do not release enough energy on their own to maintain a liquid body of water.  Chemical energy is completely useless on its own in the long term, because it requires another energy source to replenish it.  Solar fusion is the only other long-term sustainable energy source that occurs naturally and can be used by protolife for replication and evolution.  Fairly simple if you ask me.  The radiation output of Jupiter is somewhat of an anomoly, so much so that it almost qualifies as a secondary star when it comes to a source of radiation for its moons (has anyone ever figured out exactly why jupiter puts out more energy than it absorbs, anyway?) but it's still close enough in to the sun for its moons to benefit from solar radiation as well.  It suppliments energy from the sun, not replaces it.

[MatthewPapa]

Thanks for the article. Now I finally have something to write about for my English class.

[karajorma]

Originally posted by Flipside
Oh, and Kara, apparently there are suspicions of Deca-mile deep chasms in the surface of Mercury, possibly down to the mantle caused by heat splitting

I hadn't heard that. Doubt there is life in them though. Considering the heat of the surface side of mars and the lack of any solvent in which complex chemisty could happen.

Could be proved wrong though

Originally posted by StratComm
We're pretty much in agreement about everything but terminology though, if you'll read the rest of my last post.

I agree that the likelyhood of life on Mercury is low but it's not impossible by a long shot. Similarly life could exist on at least 3 of Jupiters moons, on Titan and on Triton. Given that we're now saying that life can exist anywhere between Mercury (Venus if you still can't accept the possibility of a one-face Mercury) and Uranus doesn't that make habitable zone theories a joke?
 When astrobiologists talk about habitable zones they are actually talking about that narrow area where liquid water exists. But as I've already stated that's nonsense since we can hav life without water.

So lets drop the whole concept of habitable zones and simply examine each planet on a case by case basis instead.

[Flipside]

I'm not certain they'd support life, but I'd just love to see some of this stuff before I die, the chasms on Mercury, Mons Olympus on Mars, the Methane Lakes that are suspected to be on Europa etc

Ah well, dream on Flip

[StratComm]

Methane lakes on Titan, silly

[Flipside]

LOL Oooops, yep, it's all that talk of Europa

[karajorma]

I agree flip. That stuff must look beautiful

[Flipside]

Well, it was because I used wonder what these places are like that I sort of got into rendering in the first place :-



I might actually break out Vue again, I forgot how much fun it was

[Ace]

On the subject of habitable zones, I've always considered it as: habitable for humans

Keep in mind that a lot of this search isn't really for pure science and knowledge but it's because some people want to find a sister planet to Earth for future colonization or if need be, conquest.

[Flipside]

Yep, the ultimate goal is to find a 'Sweet Spot' planet, but sometimes you can learn a lot about the ocean by looking at the stones

[Bobboau]

does anyone else think "Mu Arae" sounds like a realy cool name for a star system?

[Grey Wolf]

Decent. I really prefer the ones including the first 4 letters of the Greek alphabet though.

[Carl]

that article is wrong about the habitable zone, BTW. It doesn't need to have liquid water that is neither boiling nor frozen. some types of algae can clearly be seen thriving in the boiling yosemite nat'l park springs, and bateria has been found in core samples from miles below the arctic. both these conditions are, btw, worse for life than many places on mars, and hopefully, Europa.

[Vaelinx]

Thank you for the welcome!

Let's put the life thing into perspective.  Thus far, we have found one planet with life (still holding out for Mars though).  And even if life is found on Mars, it is far to similar to Earth (within that silly "goldilocks zone") to draw any huge conclusions about how life may originate differently than it may have here, in a cosmic sense we're neighbors.

However, we have very few data points.  We have not explored any other planetary bodies extensively.  We've scratched the surface of Mars, looked really hard at the moon...

So far, we *know* that life can be supported on this little rock we call home.  That is our only frame of reference.  Unless we can experimentally create life in another environment, we have only one data point (on the planetary scale).  Now, this does in NO way DISprove that life can come about or be supported in other environments.  We just don't know.  It also doesn't PROVE that another environment can have life.  Until we find it or create it, we cannot prove the existence of another form of life.  Without data, it's just math and conjecture.

Theoretically, life should be all over the universe...  depending on the set of theorems you start with...

I personally hope that we find life all over our solar system and hopefully galaxy.  Who knows, maybe someday we'll find some Vasudans to shoot at. Or Shivans to get kicked around by... :devil:

The other alternative is that this galaxy is a very lonely place...  We just don't know yet...  Hell, we don't even know our own origins...  But current theories say we needed water...  So we look for places out there that have water and heat and atmoshpere...  At least we can move in if noone else is home

[karajorma]

You're welcome Vaelinx.

I agree with you fully about us only having one data point. Which is why I find it so silly to extrapolate from that and say life can only exist on an Earth like world.

Personally I would love to see life found on Europa or evidence of it having existed (or for that matter still exisiting) on Mars.

[Flipside]

Carl Sagan came up with a hypothetical lifeform that swam in the mineral-rich outer layers of Gas Giants in very much the same way as deep sea lifeforms operate in, what we believed to be, 'non-life capable' water on Earth, if you can track down the book 'Cosmos', it's old, but very well worth a read

[karajorma]

I'm currently reading "What does a martian look like" by Jack Cohen and Ian Stewart. It's a pretty interesting book on what might be out there