The case against “geospermia” here is vastly overstated: there’s been a lot of research over the past decade or two establishing very plausible pathways for terrestrial abiogensis. If you’re interested, read through some work coming out of Jack Szostak’s lab (there’s a recent review article here). I’m not as familiar with the literature on prebiotic chemistry as I am with the literature on protocell formation, but I know we’ve found amino acids on meteorites, and it wouldn’t be surprising if they and perhaps some other molecules which are important to life were introduced to earth through meteorites rather than natural syntheses.
But in terms of cell formation, the null hypothesis should probably be that it occured on Earth. Panspermia isn’t ridiculous per se, but conditions on Earth appear to have been much more suitable for cell formation than those of the surrounding neighborhood, and sufficiently suitable that terrestrial abiogensis isn’t implausible in the least. When it comes to ways in which there could be wild-animal suffering on a galactic scale, I think the possibility of humans spreading life through space colonization is far more concerning.
Also, Zubrin writes:
Furthermore, it needs to be understood that the conceit that life originated on Earth is quite extraordinary. There are over 400 billion of stars in our galaxy, with multiple planets orbiting many of them. There are 51 billion hectares on Earth. The probability that life first originated on Earth, rather than another world, is thus comparable to the probability that the first human on our planet was born on any particular 0.1 hectare lot chosen at random, for example my backyard. It really requires evidence, not merely an excuse for lack of evidence, to be supported.
This is poor reasoning. A better metaphor would be that we’re looking at a universe with no water except for a small pond somewhere, and wondering where the fish that currently live in that pond evolved. If water is so rare, why shouldn’t we be confused that the pond exists in the first place? Anthropic principle (but be careful with this). Disclaimer: Picking this out because I thought it was the most interesting part in the piece, not because I went looking for bad metaphors.
As a meta-note, I was a little suspicious of this piece based on some bad signaling (the bio indicates potential bias, tables are made through screenshots, the article looks like it wants to be in a journal but is hosted on a private blog). I don’t like judging things based on potentially spurious signals, but this might have nevertheless biased me a bit and I’m updating slightly in the direction of those signals being valuable.
The case against “geospermia” here is vastly overstated: there’s been a lot of research over the past decade or two establishing very plausible pathways for terrestrial abiogensis. If you’re interested, read through some work coming out of Jack Szostak’s lab (there’s a recent review article here). I’m not as familiar with the literature on prebiotic chemistry as I am with the literature on protocell formation, but I know we’ve found amino acids on meteorites, and it wouldn’t be surprising if they and perhaps some other molecules which are important to life were introduced to earth through meteorites rather than natural syntheses.
But in terms of cell formation, the null hypothesis should probably be that it occured on Earth. Panspermia isn’t ridiculous per se, but conditions on Earth appear to have been much more suitable for cell formation than those of the surrounding neighborhood, and sufficiently suitable that terrestrial abiogensis isn’t implausible in the least. When it comes to ways in which there could be wild-animal suffering on a galactic scale, I think the possibility of humans spreading life through space colonization is far more concerning.
Also, Zubrin writes:
This is poor reasoning. A better metaphor would be that we’re looking at a universe with no water except for a small pond somewhere, and wondering where the fish that currently live in that pond evolved. If water is so rare, why shouldn’t we be confused that the pond exists in the first place? Anthropic principle (but be careful with this). Disclaimer: Picking this out because I thought it was the most interesting part in the piece, not because I went looking for bad metaphors.
As a meta-note, I was a little suspicious of this piece based on some bad signaling (the bio indicates potential bias, tables are made through screenshots, the article looks like it wants to be in a journal but is hosted on a private blog). I don’t like judging things based on potentially spurious signals, but this might have nevertheless biased me a bit and I’m updating slightly in the direction of those signals being valuable.