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Comment by westmeal | Hacker News Reader

Proponents of panspermia are pretty happy about this finding I bet.

To be perfectly honest, you’ve drawn my attention to an ambiguity I had never before noticed: does panspermia’s hypothesis that “life” came from space require that life arrive fully formed and functional, or does it advocate that complex organic chemicals arrived from space and assembled on earth into a working configuration?

I have always found the idea of panspermia to be a bit of a cop-out as it totally sidesteps the problem of abiogenesis: it’s all fine and well to say “life came from space” but you still need to explain how life arose in space to begin with.

I'm not an expert, but I think that there are different flavors of panspermia. Some would say that we got at least single-celled organisms from space; others would say that we just got complex chemicals.

It's only a cop-out if you try to use it to explain the origin of life in general, not just on Earth.

Life arose very quickly on Earth, almost as soon as it was capable of surviving, so it raises the interesting question: were we just lucky, or is it easy to spawn life, or did it come from elsewhere? The answer creates very different pictures for what Earth-like planets elsewhere in the galaxy actually look like.

I'm always confused by that. So there's only one form of life possible? Otherwise life may have arisen before, been wiped out when Earth changed, and life arose again. We may be just the latest in a long series of life forms.

Good point. It might be that the kind of life that arises on a planet depends on what it is bombarded with and which of those various candidate life-forms ‘takes’ on the specific environment.

theoretically possible but there is no evidence to suggest this. Weighing the various hypotheses, most people would suggest the "simpler" (fewer wipeout/arise events) hypothesis, given the assumption that life arising is considered very rare.

Because the earth remade itself several times. Any previous life would have surely been erased. The assertion was that life arose just once. That's hard to prove.

From what I've read there are people on both ends of the debate. Most people I've seen talking about the idea tend to lean towards amino acid and simple proteins making it down here - not fully functional lifeforms that are able to replicate.

A panspermia theory that involved non-living chemicals coming to Earth would be pretty useless. There's no real doubt that it's possible to generate those chemicals on Earth, and AFAIK it's still believed to be easier to make them on Earth than in space. Organic chemicals from space would just mix with all the ones that were already here.

>> it's still believed to be easier to make them on Earth than in space

I don't mean to be glib, but space is very large and time before our planet was formed is very long.

I assume that if it was easy here in those first few hundred million years, it had already been even easier in many elsewhere places. Any one, or multiples of which could have seeded us with as yet locally unavailable precursors and possibly even life.

I think a complex molecule could accepted. We don't know why our biological systems settled on their chirality, but maybe it was from a massive bump of molecules with all the same chirality from an extra-solar source.

https://en.wikipedia.org/wiki/Chirality_(chemistry)#In_bioch...

While I have no objection to panspermia being possible, if it were true, it would be a significant hurtle added to the search for the origins of life. We would know how life on Earth started, but until we expand out into the galaxy, understanding the origins of the life that seeded Earth would be essentially unknowable.

At the same time, it's pretty clear we need to get out there (ultimately much beyond the galaxy itself) if we are to solve certain questions.

And there's a general idea that a purpose of life may be to "spread" through the universe — like, why die here on this planet instead of settling the universe... given the actual choice, there's no solution but to leave eventually, when your star dies (if only locally to "fix" it by adding more fuel in it, e.g. hydrogen).

So this, if true, is really just one more reason on top of an already high pile as I see it.

Assuming panspermia is correct, we could just continue to improve sampling of stuff coming here. Also sampling earth-originated organic materials from some distance away. This could give us some pretty good data on variety, density, duration.

Under this assumption I'd most like to estimate the number of discrete seeders in our vicinity and their interconnectedness.

"The team's paper has not yet been peer reviewed"..

At the best of times, what exactly does peer review add? I'll buy that it catches glaring flaws in their methodology or conclusions drawn from data. But it's not going to catch little mistakes or unlikely events that might have contaminated the sample.

For the purposes of a site like this, peer review filters out the cranks. Cranks can be rather a burden on people: they rarely accept criticism well, and effort spent explaining the problems to their defenders is a drain without a lot of upside.

So when somebody can say "It has been peer reviewed", it at least helps get past the crank filter. And conversely, "It hasn't been peer reviewed" can be a shortcut for "I'm not going to put a lot of effort into this without better reason than I've heard so far."

It's not so much an argument as a way of shortcutting an argument. Though note that doesn't really apply to a top-level comment on HN, where nobody has really advanced an argument yet and simply ignoring it might be a more useful strategy.

this is why we dont do one offs.

there has to be independently reproducable results from independent research over time until the variation of outcomes is known, for some sciences this can be a very long process for very unscientific reasons.

one thing not addressed is that the isotopic elements of the meteoric fragment may have been incorporated by a terrestrial biological or chemical process

Right - but reproducibility is distinct from peer review. Stuff that has been peer reviewed is very often not reproduced (or reproducible).

whenever the methodologies of a scientific experiment are repeated the underlying principle is preserved if there is no signifigant deviation of observed results from expected results.

for example PCR has a lot of credit, the central dogma of molecular genetics has a lot of credit, but there are exceptions being found in very niche cases such as reverse transcriptase and the HIV virus.

those experimental protocols that have been reviewed and found to be non deficient at the time of review are often repeated in principle as they are used for a common tool.

Proponents of panspermia still pretty happy, nevertheless.

It might hurt humanity's pride if this material turns out to be dejects spewn from passing spaceships.

Possibly, but the explanatory power of your little theorem is rather substantial.

that's a concept that reminds me of Roadside Picnic.

The impact of a collision is so devastating that any life surviving it is unlikely. Unless such life can endure such extreme conditions, in which case, it would exist on such inhospitable conditions as on Venus

So far sugars, and amino acids have been found in both comets & gas clouds. BUT to find this protein is the slam-dunk, holy-shit they were right, proof that Panspermia is how we got here, and there _MUST_ be life in other parts of the universe.

I agree with the last part: it probably shows that there’s life out there.

It could show that life travelled here on meteorites etc. But it also could mean: life arises elsewhere, life commonly arises in the universe and may have also arisen here (and many places) independently.

> "proof that Panspermia is how we got here"

How so? "We" could predate this protein.

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