So it seems there is only an either / or question regarding Life's origins.

Where do we stand as a community?

Either Life originated on earth through abiogenesis Or was transported here from elsewhere, aka panspermia.

Please vote.

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"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

I voted abiogenesis.

Panspermia can mean 2 things: That life started in space (e.g. inside a nebula or high orbit of exo-planet and floated into space) OR it started by abiogenesis ON ANOTHET PLANET and survived a flight through space to reach Earth and rain down (e.g. Earth life came from Mars by meteorite originating from Mars' surface).

I'm going to apply Occam's Razor now, and pick abiogenesis on Earth as the most likely scenario. The right ingredients were all there. Nothing on Earth seems to have PREVENTED life from starting here, so abiogenesis on Earth seems a more likely option opposed to extra-planetary abiogenesis + surviving space flight.

I'm not sure about the odds of life forming in space itself. Is there any reason to suspect that a nebula passed through our solar system 4 or 5 billion years ago and deposited proto-life on Earth? If not, then the odds of panspermia don't seem so good for that option.

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This user is currently on a smooth slope of Mount Improbable

Are you asking the question about life on Earth, or life in general in the universe?
If it is the former, the answer could be either, with a somewhat smaller chance of life starting elsewhere in the solar system and migrating here. Mars is the most likely candidate.
Lithopanspermia between stars in a cluster is also a very small possibility.

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If it is about life in the universe as a whole, then all life started originally by abiogenesis, whether or not it has been subsequently transported by lithopanspemia or translocation by intelligent species.

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Orion's Arm . The Starlark . Voices: Future Tense . OA Flickr set

I know that life that supposedly came to Earth as in a panspermia-theory-like fashion would have started by abiogenesis in space. I'll aply the term abiogenesis a bit more careful

Would you say 1) the odds of life forming in outer space are bettr than the odds of life forming on Earth?
Or 2) do you think panspermia-theory a likely candidate for 'seeding' Earth because life would have had more time to develop? (The Universe is older than the Earth, and life has had more time to form in space/nebulae, etc, long before Earth existed.)

The options are not mutually exclusive per se, but I have my doubts about number one.

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This user is currently on a smooth slope of Mount Improbable

I should've capitlaized "Earth" in the OP; Life on Earth origins (to answer your question, eburacum), as in primordial soup hypothesis...

I find it a conundrum somehow but can't quite articulate it at this time...
more interested in the poll results really...

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"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

I'd go with an Earthly origin, just because the conditions in space are less than conducive to life. Could early life have come here from Mars? Possible, but 1) it would need to survive the trip, which would be no easy matter even for today's highly-evolved lifeforms with 5 billion years of survival adaptations, and 2) there's no reason to think Mars would be more likely to develop life than Earth.

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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

Oh, forgot to address the comet hypothesis. No dice there, a comet wouldn't have enough energy or any liquid water to support life. Even heat from the sun only sublimes off the outer layers, taking both heat and volatiles into space.

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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

Occam's Razor tell us that 1. option; abiogenesis, is the most probable, but one don't know, it well might be panspermia..

So I vote abiogenesis, because it is the most probable..

But if you some take organics and water from meteors, asteroids and comets, as a variant of panspermia; then I will vote panspermia, but only precursors for life were transported to Earth - the rest was done here.

Abiogenesis. Even if it didn't start here, it started somewhere.

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"I always look for a woman who has a tattoo. I see a woman with a tattoo, and I'm thinking, 'OK, here's a gal who's capable of making a decision she'll regret in the future.'"- Richard Jeni.

I suspect abiogenesis on Earth. It doesn't mean panspermia or CA is impossible, just unlikely, in my opinion.

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

Technically, since Earth was formed by planetoids which clumped into planetesimals and then into planets, all water and organic chemicals on Earth did start out in comets and asteroids.

__________________
"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 vote abiogenesis, life as an inevitable extension of carbon chemistry, the properties of liquid water.

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plenty of woo, at the hotel hoagaland...

I'd guess abiogenesis on Earth, but there are so many varieties of possible, if unlikely, transfers of life between planets and other domains. Abiogenesis on Mars with a subsequent move to Earth would be interesting.

After that there are many conceivable levels right up to galactic or even universal panspermia. I don't think they are probable, but what do I know?

If I had to guess, I'd say sparsely distributed independent biospheres with occasional cross transfers within a solar system.

Our data, with a sample size of 1, are a little sparse. Abiogenesis on Earth seems to involve a smaller chain of unlikely events, so that's the way I'm voting. I'd put some money on it, but not all my savings.

Actually, I think we've got a sample size of three, maybe more. One of the planets shoes signs of life and another presents evidence of past life, but is itself too small a sampling to be sure. The other objects currently show no signs of present or past life.

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

If you mean the Mars meteor, that hasn't been confirmed yet as having evidence of Martian life. What other planet has signs of life?

__________________
"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

That's what I mean, it's inconclusive, but it is still part of the sample set, along with Luna and possibly Titan, Eros, and perhaps we should include Venus too since we've landed on all of them.

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

Um.

I guess I just don't understand what you mean. Earth is still the only planet confirmed to have evidence of life. Mars has questionable data that might show evidence, or might not. None of the other planets/moons mentioned have shown any evidence, at present all we have is speculation, based on a few possibilities.

That still leaves just one planet with life.

__________________
"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

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PW -- Plant Whisperer