By themselves- no, not necessarily. An atmosphere is probably required to support life, but by itself, it's not enough- a crushing atmosphere or one that is too thin or too toxic doesn't say so much. As far as we know, the conditions seem very particular, or you'd be seeing life on the terrestrial type worlds like Venus, Mercury, Mars, the moons in the solar system, as such.




See above, or else what about that do you specically think is negligible? So you're saying that if a planet has one side that's hot enough to melt lead, and the other that's made of frozen ammonia in perpetual darkness because it spins very slowly is a non factor? What makes you think that's dissmissible?

Well if given the extremes you mention, then that's another consideration.
I'm just saying the parameters that would support intelligent life are likely much more wide
than you're taking into account - if I understood your post correctly.

For all we know there are technologically advanced races that are not even carbon based, but silicon based, and live
in conditions that would kill us instantly. Our atmosphere might do the same to them.

Tidal forces certainly will the conditions for life- on other planets this is rather a disadvantage, say for example one that has a side that always faces the sun or is orbiting a large body with a tremendous gravity field. On Earth, the right combination of things happening is astonishing, including a moon of just the right size.

It appears to me from the evidence that the window for life is pretty narrow- otherwise, there's no reason that Earth is so special and you wouldn't be seeing it in more places in our solar system. Moreoever, the arguments are always like "Well, it could be silicon-based;" which nicely ties up the loose ends to speculate than anything could be possible such as that. Then again, why aren't we seeing that- that seems even more likely than carbon based life-forms, given the amount of rocky worlds with harsh environments, that would seem more likely to be flourishing everywhere. You can always speculate that life might be something that could survive in clouds of sulfuric acid on Venus or in a gaseous environment with atmospheric pressure hundreds of times that of Earth deep down in Saturn or something- there's no way to disprove that for the time being, it remains unfalsifiable.

I think life and intelligent life are quite rare. Even if it argued that the chances are very high there is intelligent life everywhere in the universe, I think on relatively local scales, that is, in practical reach, are rare if practically non-existent.

For this reason I think things like SETI are over-optimistic, it basically works off the presumption that at a given moment they are going to tune into an alien signal. These broadcasts would have to be within relatively short range, radio waves are subject to the inverse square law, given enough distance they will attenuate to be indistinguishable to cosmic noise and buried within all the other cosmic radiation.

Our solar system is representative of the tiniest fraction of all possible planetary conditions, and an
in comprehensibly tiny fraction of all the planets in the universe.

What I'm saying is that if life is so abundant in the Universe, it should be so abundant locally as well. There's no reason why it would happen only on Earth and not on the other terrestirial worlds and planetary moons in our Solar System for the same reasons- they underwent similar conditions in the primordial state, yet, we only see it here on Earth. This seems to me indicative of what we're dealing with.

If people expect to see silicon based life forms popping up to counter the apparent problem with few worlds with conditions that are Earth-like, why aren't we seeing that in our solar system, or else why aren't we seeing that on Earth? Why aren't these things all around us here on Earth? I think people just join speculation with more hope that could happen than the chances of that actually happening. Even with species like cockroaches and certain bacteria which are capable of surviving under much more severe conditions, there's no evidence of those on the Moon or on Mars, either. It therefore follows that they couldn't evolve on Venus or Mercury, either, since conditions on those planets are worse. Those types of planets are typical- just the wrong conditions. There are many, many of them. But the odds of one of them with the right conditions within local reach- just really hoping against hope.

That logic doesn't follow, thus my post above.

And life IS abundant locally, out of 9 or so planets there's at least one that has life on it.


You post is like sitting in the middle of the desert and saying "if eagles are so common worldwide, I should be seeing
them all around me right now"

Our solar system is like one grain of sand sitting amongst all the other grains of sand on all the beaches in
all the world.

It does follow- you just don't agree with the conlusion. Logic is simply just that the conclusion follows logically from the premise, it doesn't mean that it's true or that it corresponds to a real thing. The premise doesn't even have to be true for a statement to be logical. But if logic is all we have, because we have no physical examples of this anywhere else, then it's my logic against yours.



No- all that shows is that life is unique here on Earth in our Solar system, not that it's abundant (and Pluto has been downgraded- no longer a planet). It's abundant here on Earth, it's apparently rare though outside of that little sample.




Yours are based on what- idle speculation. Even though you've not seen life anywhere else, it must be the case that it's abundant because, well, the chances are likely. Yet you have no evidence for that- pure thought experiment. Your line of thinking is like trying to prove that God exists- even though there is no emirical data to support that, you exercise imagination for it. Under any other circumstance if I asked you there was an elephant in the room, you would say no, since there is no way to detect one. For certain other things though- God, aliens, astrology, paranormal activity, our measurements simply tossed out for what we wish to be true.

Once again, if life is abundant in the Universe, it doesn't mean that it's abundant anywhere within a million light years or us. Life could be all over the place, but because the universe is so vast, on a local scale this is meaningless to us.

Can you answer this question- why not life on Mars? Why aren't we seeing silicon life forms there? What's the reason for that?

It absolutely doesn't.
You're not following, but I don't have the time really to explain further.

Cheers

I always find these kinds of epistemolgical explorations to be the oddest kind- someone who has no proof anything 'knows' that it's so obvious that alien life is everywhere- yet could never show that to me. That doesn't usually work for most other thought processes.

I'm the skeptic, I need to be convinced. I've neard heard of an alien. I've never seen one, I've never seen any concrete evidence that someone else has. Tell me what I'm supposed to be seeing here. This sounds to me like a lot of superstition that gets passed around- in other words, no connection at all between belief and what materially exists, but I would certainly amend my thinking if I actually had something to work with.

Classic cop out to say "Nope, I'm leaving."

Seriously, the day that one of you shows me something verifiable, then it becomes a verifiable fact. Until then, speculation is what you and I both have, and then it's a matter whose ideas are more convincing. So far, I've not seen you explain why life hasn't evolved on other planets or moons in the Solar system, that's just conceding to me what I've been saying- that conditions on earth that life requires are probably very, very rare.