how are we(life on this planet) not "that special"?

Maybe we are, maybe we aint, there is no way to tell yet, there maybe billions of life supporting planets, all special.

__________________

I meant not special enough to 'cause the Universe to happen.' It's ususally a religious argument that 'the Universe was created for us' (by god or gods), but there is no reason to think our existence is somehow directly related to the Universe as a whole. I think we're more coincidental byproducts. We could be wiped out and the Universe would be unaffected.

If rare equals special, then life is pretty special :P

__________________
This user is currently on a smooth slope of Mount Improbable

Coincidental byproducts...I like that.

When we talk about life we have to assume we are describing organic life as we know and understand it. Therefore carbon based water using oxygen and carbondioxide exchanging life forms. Speculative SciFi ideas of pure energy beings whilst being nice things to ponder surely do not form part of this debate. Given that:

1. I don't really see a Nebula being a good place for life to start up the energies may be high but the conditions unstable.

2. Comets and asteroids as has already been explained do not offer good environments for life to get going - alternating as they do between being in deep-freeze and boil-off conditions. Surely conditions on the early earth would be a better place for life to start than on/in a comet. Just because comets my contain organic chemicals does not make them good nurseries. Planets are larger - therefore if the planet is the right sort it will have a bigger pool precursor chemicals to experiment with - Therefore if you take an early earth-like planet and a comet and sit around for a few billion years and watch them my bet is life would get going on the planet before it did on the comet.

3. Life being brought in carried on objects from beyond our solar system. While one cannot exclude the possibility of this 100%, I have to say that the journey times involved and more critically the probability of something having some viable spores just happening to impact the earth at just the right moment (that is after the planet has cooled down sufficently to allow organisms to survive) seem to be a very low probability event.

4. Life being brought here from Mars. All we can say is that it looks like Mars had suitible conditions to support life sooner after its formation than earth did. However those condidtions did not last and as to whether life ever got going there - Well the Jury is till out. If Mars is found to still support life then of course a very thorough examination of its genetic material will be needed to determine if it shares any characteristics with what we know about primitive life here - if however possesses the characteristics of modern bacteria then we must be careful to eliminate the possibility of contamination through human activity. If we only find evidence of fossil life on Mars then then providing we can identify that it predates life on earth then the possibility of the transfer of life to earth may (I say again) may be considered. However until we have conclusive evidence of Martian life (and no data or samples we have today provide that) then suggesting life came here from there pointless.

That then brings us back to life getting going here all on its own. It is here that I have a problem with the Panspermia supporters. -

What was so wrong with the early earth for life to get started here?
This planet sits in the optimum distance from the sun it had all the right ingredients and a sufficient mass/volume of liquid water to act as a support medium.

So why throw in other things like comets - I see nothing to suggest that a comet is a better place for life to get started.

As to life evolving on a planet in another star system. Then if that planet shares/shared similar conditions to earth (but sooner) then why not. However the probability of any of its organic material reaching us seems far less likely than things getting going here all on their own.

Now here we have an interesting puzzle.

We do not yet know how often on a planet similar to ours life actually gets going. As a result of recent exo-planet discoveries I think it is safe to assume that there are at least some more small rocky planets with liquid water orbiting their stars in the "goldielocks" zone. Of course we do not know if 1in100 1in1,000 or 1in10,000 star systems have such planets. Nor do we know if on all such planets that at least by the time they are 4 billion years old that life on them will be fully established. For all we know some of these worlds may remain nothing more than chemical soups until their star dies. It could be that on only 1in1,000 planets experiences the events that lead to the appearance of life or it could be 1in1 - again we have no idea.

Here however is the contradiction:

If the emergence of life is a rare event on an eathlike planet then that makes Pansermia seemingly attractive as that one lucky world then goes on to seed the galaxy. But that is problem the chances of its spores actually reaching anywhere viable are too low to consider it as a viable source.

On the other hand if on a planet like ours the emergence of life is a forgone conclusion - then you don't need Panspermia - because life is just bound to emerge all on its own.

So I have to say this:

Abiogenisis - is the only logical position to take for now with the remote possibility that we re-open the case and examine the facts if we ever find evidence of native Martian life.

__________________
Note 1. All requests for planetary demolition must now be submitted in quadruplicate on form UX-565/B4 and be counter-signed by the assistant administrative officer for interstellar traffic calming - department QG-7. Subject to approval by the chief planning officer and the infrastructure development coordination sub-committee.

Yes, that was rather the point.

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

Let's see:
No, he didn't say which one he was referring to. I saw "a sample size of one", and "the set of known life-bearing planets" does fit that description nicely, so I assumed that was what you were referring to as well...

__________________
"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

Except that second quote wasn't in the post I was referring to, so there was no reason to assume it.

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

What post, then, were you referring to?

__________________
"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

Reminds me of how lawyers shouldn't ask questions unless they already know what the answers will be.

How do you know I didn't already suppose the poll results would be as they are?

Of course, this simply reflects that closer to the mainstream trunk of the tree of Science is a safer place for birds. I think the more delectable seeds and fruits of discovery are found further out on the limbs.

But we're all strange birds in our own right.

__________________
"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

"Men occasionally stumble over the truth, but most pick themselves up and hurry off as if nothing had happened." - Churchill

As the poster whose "sample size of 1" comment sparked all this, I'd like to reply.

I wasn't talking about planets at all. The question concerns the origin of life. Our explanation needs to fit all known instances of life originating. How many instances (known, not speculated about) of life originating do we know about? Anyone get an answer other than 1? Thought not.

Oh yes...of course it MUST be because those 23+ posters are "playing it safe" with their belief in scientific "dogma".

It couldn't possibily be that those 23+ posters have rationally examined the evidence for panspermia and found it wanting...no it couldn't be that.

You ask for opinions, then just handwave those opinions away with a "for the birds" comment.

Can't you see how insulting that might be to those who took the time to respond??

The reason the scientific mainstream is mainstream is that it's been examined, scrutinized, and tested, and is consistent with observation. Not because it's "safe".

ADDED: What's "mainstream" also changes as more data becomes available.

__________________
"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

Conspiratorial coincidental byproducts would be more accurate

__________________
PW -- Plant Whisperer

Indeed, it does.

But perhaps I could've chosen a different word than "safe."
I was trying to convey the notion that scientists would rather err on the side of caution.

__________________
"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

"Men occasionally stumble over the truth, but most pick themselves up and hurry off as if nothing had happened." - Churchill

When it comes to confirming statements as accurate, yes, as well they should.

__________________
"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

Sorry I still cannot see it - this debate keeps popping up time and time again under various titles and I still do not get it. Now if I really am stupid then I wish someone would explain why I am so.

Despite having read links posted by those who support Panspermia I have still not seen anything to indicate why it has to be a better option than Abiogenesis.

People talk about us not knowing how the first living cells got going on earth - OK so we don't have the details yet but that does not prove that because we cannot work out exactly how something happened here that it had to happen somewhere else. Unless that somewhere else offers some sort of solution to suggest that it overcomes certain critical problems of life trying to originate here on earth. Whenever I ask this question about what this better place for the origin of life would have been I never get a clear cut answer. All I get are veiled references to Comets and Nebulae - none of which from a biochemistry perspective seems to be any better than the early earth. SO WHAT! if comets carry precursor organic chemicals. Those chemicals are NOT LIFE. Even if those chemicals came to earth on comets that does not prove Pansermia all it proves is tha Abiogenesis needed some raw materials from space in order to get going.

Instead of arguing about the validity or not of this or that Scientist's opinions will somebody PLEASE PLEASE PLEASE explain in simple step by step terms why it is more likely that life could get started somewhere else than on the early earth. Could they please define precisely why the conditions here a few billion years ago were not adequate for life to get going by itself and why some other place had better conditions and what those particular conditions were there, which did not exist here.

Then maybe just maybe I might be more open-minded to the notion of Panspermia (though possibly not a convert). All I ever seem to hear is that because it was improbable for life to get going here, then it must have started elsewhere. That simply is twisted reasoning. If the emergence of life was improbable event here then it follows it is an improbable event anywhere.

So PLEASE no more links to articles talking about how chemicals for life could have been brought to earth from space. No more links to articles that suggest that life has been around longer than the Big Bang. No more links to articles trying to justify the Steady State Universe. No more links to articles that talk about how the spores of life could be carried through space. All of that is irrelevant. All that matters is this:

1. Organic life as we know it had to get started somwhere.
2. If it could not get started here all by itself then WHY NOT.
3 If it could get started in another place then WHY WAS THAT PLACE BETTER.

How it was transported here and whether there was much probability of it actually reaching the earth crossing 10s or 100s of light years of space is less relevant than answering the three simple questions above.

__________________
Note 1. All requests for planetary demolition must now be submitted in quadruplicate on form UX-565/B4 and be counter-signed by the assistant administrative officer for interstellar traffic calming - department QG-7. Subject to approval by the chief planning officer and the infrastructure development coordination sub-committee.