Someone let the panspermists out of their cages again

I’m rather astonished that Salon chose to publish this article, Why some scientists believe life may have started on Mars. The operative words in that title are some – we’re talking about a tiny fringe minority – and believe, because they sure don’t have any evidence for their ideas. I guess Salon is desperate for news, so they’re letting writers invent some.

They don’t provide any evidence for their claim, only a weak chain of rationalizations.

  • Some Mars rocks have been found on Earth. True enough. Meteor collisions with Mars can splash rocks into space, and they occasionally fall to Earth.
  • Maybe early Martian life was adapted to survive meteor impacts, and was so hardy it could have survived the accidental launch and long journey? I had to laugh. Nothing evolves to survive meteor impacts.
  • Maybe early life was fine with harsh environments? Early life would have been adapted to aqueous environments; “harsh” is floating away from food sources and warmth and a predictable pH, not drying out completely and surviving a vacuum.
  • Life on Earth evolved “quickly”, too quickly. Yeah, we think replicators evolved shortly after the planet cooled enough to have liquid water. We’re talking within…200 million years. That’s not enough time? How do you know?
  • Mars cooled before Earth, therefore life could have evolved there first. Wait, you think 200 million years is inadequate for life to evolve on Earth, but there was time enough for it to evolve on Mars?

The real reason this fact-free idea is getting promoted is because a couple of crackpots from Harvard, Gary Ruvkun and Avi Loeb (remember him? The Oumuamua guy?) said it, and “Harvard” is a magical incantation to the rubes. They don’t have a speck of evidence, though. It all sounds like something someone would have babbled about over lunch, and then the speculation went critical, and because they’re Harvard guys, they think it’s worth announcing to the news agencies. That’s it. That’s all this is.

They’re not even particularly clever Harvard guys.

“To me the idea that it all started on Earth, and every single solar system has their own little evolution of life happening, and they’re all independent — it just seems kind of dumb,” Ruvkun said. “It’s so much more explanatory to say ‘no, it’s spreading, it’s spreading all across the universe, and we caught it too, it didn’t start here,” he added. “And in this moment during the pandemic — what a great moment to pitch the idea. Maybe people will finally believe it.”

“Seems kind of dumb” is not an argument. It seems kind of dumb to me to suggest that the first life on earth, which would have been fragile and relatively simple, happened to be so robust and stable that it could have survived a massive shock that threw it into space, where it drifted for hundreds of thousands, even millions of years, in a vacuum, bathing in radiation, to survive a super-heated re-entry to an alien atmosphere, crashing to Earth to resume where it left off on a Martian ocean. And that this was a more significant contribution to early life than countless chemical reactions churning out organic molecules at the bottom of Earth’s oceans.

These people are fine with reciting silly arguments about the great improbability of chemicals coming together to form a self-perpetuating metabolism, but hey, chance survivors on rare random rocks flung into an immensely empty space happening to coincidentally hit a dot of a world a hundred million kilometers away, or even hundreds of light years away, no problem.

And they think a pandemic will help them? Aside from the tastelessness of that notion, we can’t even convince millions of people to wear a mask, yet they think this will convince them that we’re all descendants of Martians? At best it means these guys think people are gullible enough to fall for their crackpot ideas now.


  1. chrislawson says

    This is just bizarre. I remember astronomers talking about this hypothesis with interest after some discoveries on Mars about 10? 20? years ago, but even then they had the sense to express their ideas with great caution and label it as speculation.

    Avi Loeb’s schtick is to take other people’s conjectures and regurgitate them without any of the nuance or qualification and then insist other people are being arrogant for not jumping on board uncritically. It’s not clever at all.

  2. blf says

    A pandemic convinces people of panspermia because the words are spelled so similarly. (Proof by spelling… QED)

  3. chrislawson says

    Also, any life that is well adapted to interplanetary space rocks would find Earth the hostile environment.

    I don’t consider it confirmed as impossible that some micro-organisms arose and evolved on Mars that might survive a meteor blast and expulsion into space, years (possibly millennia) in vacuum and direct solar irradiation, followed by the heat of entry into Earth’s atmosphere, only to land in the right environmental envelope and then thrive here while the entire biosphere collapsed to extinction on the home planet to which it was adapted…but it’s not arrogant to find this hypothesis less compelling than that life adapted to Earth started here.

  4. says

    Panspermia is an interesting and completely unprovable idea. It sells well in popular culture, but so does Bigfoot, ghost hunting and ancient aliens.

  5. raven says

    And they think a pandemic will help them?

    That we are in the midst of a Coronavirus pandemic is irrelevant.
    The Covid-19 virus is not on its way to Mars or anywhere else in the universe.
    In fact, it needs vertebrate hosts to even replicate.

    It all sounds like something someone would have babbled about over lunch,..

    I was thinking more late at night, after a bit of marijuana and cheap wine, while listening to hard rock, with a few candles burning.

  6. bcw bcw says

    Should we find signs of life on Mars, it’s seems more plausible to think it came from all the teaming pestilence of Earth than that Earth’s life came from there.

  7. christoph says

    “I had to laugh. Nothing evolves to survive meteor impacts.”
    Oh, I don’t know. Ever see “A Quiet Place?”

  8. slithey tove (twas brillig (stevem)) says

    amazing how they use probability without understanding it in the least.
    IE: No matter how small the chance of something happening, given enough trials it is essentially certain to happen. The concept of the number of trials the primordial soup provided completely escapes their limited imagination.
    EG two people having the same birthday has a probability of 1 in 365*365, out of a group of 30 people the probability of two having the same birthday is close 50%, increase the sample size the probability of NOT finding it drops exponentially. Seems to improbability argument only looks at the probability of an isolated occurrence of a single trial, never considering the total population of samples occurring. harrumph

  9. says

    @9 ST
    Two people having the same birthday is a 1 in 365 chance not a 1 in (365*365) chance. That would be the probability of three people sharing the same birthday. Still your point holds, I’m just being pedantic.

  10. chrislawson says

    Yep. The Miller-Urey experiment created complex organic molecules in 5 litre flask running sparks for a week. Signs were there from the first day but they didn’t open the flask to test it until the week was up to avoid contamination. While there’s a lot of debate about how closely the Miller-Urey experiment matches the early Earth environment, it still shows that complex organic molecules can arise from simple ingredients (water, ammonia, hydrogen, methane) + energy. And they were only looking for amino acids.

    I don’t think it’s possible to do this calculation with precision, but an estimate should suffice. The Earth has around 1.4 x 10^21 kg of water. I’ll use PZ’s 200 million year estimate for the window for life to form, which gives us 7.3 x 10^11 days. The M-U experiment used only 500g of water. So the early Earth had 2 x 10^33 Miller-Ureys to work with. If you want to go conservative and insist on using 5 days instead of one, this is still 4 x 10^32 Miller-Ureys. (This is very back-of-the-envelope. Corrections welcomed.)

    Just for a sense of scale, 10^32 is a hundred billion times the number of stars in the observable universe.

  11. chrislawson says

    Whoops. 7.3 x 10^10 days. Scale everything back by one order of magnitude. So that’s only ten billion times the number of stars in the observable universe.

  12. chrislawson says

    That’s what comes from doing these things in my head instead of using the actual back of an envelope.

  13. yaque says


    Long time lurker here:
    Something I always wanted to know.
    Assuming life arose in an alkaline hydrothermal vent (black smoker) in roughly 200 million years.
    How many of these things are there at any one time over the earth? thousands? millions?
    How many vesicles (natural microscopic “pits” about the size of … hmmm… cells) in each smoker? trillions? quadrillions?
    How many exotic chemical reactions per second? X 200 million years?
    A lot, I’d wager. Enough for almost anything to happen ….

    So, I would really be grateful if any of you scientist types who know about this stuff could fill in my guesswork with actual, genuine, sciency back-of-the-envelope numbers!

  14. chrislawson says

    This is what comes from juggling numbers in my head instead of using the actual back of an envelope.

  15. says

    @yaque 14
    The alkaline vents are not “black smokers”, those are young “magmatic vents” and as they age the older parts become “white smokers” as a field ages.

    The alkaline hydrothermal vents are produced by a chemical reaction between ultramafic rock like olivine called serpentization.
    I have a source somewhere that mentions these would have been more common on the young earth. The other vents and carbon sources contribute to the ocean chemistry.

  16. tacitus says

    A pandemic convinces people of panspermia because the words are spelled so similarly. (Proof by spelling… QED)

    Phyllis Schlafly’s idiot son Andrew has long been waging a personal crusade against relativity because he believes the Einstein’s theory has played a significant part in the rising popularity of relativism over “absolute truth”. (Basically he believes everything about modern physics from Einstein onwards is a liberal atheistic plot to destroy Christianity.)

    Even his own brother’s efforts to dissuade him of such delusions have been futile.

  17. tacitus says

    I wonder if this fascination with panspermia is driven by something akin to the religious or spiritual feeling many people subscribe to — that we are not alone and that there has got to be something more to life and/or the universe than this.

    I’ve long thought that the final step from “not religious” to atheist is the toughest step for most people to make, and that even as many people are deserting Christianity and other organized religions, most still cling to that vague belief there is “something more” as a kind of spiritual security blanket.

    While panspermia cannot ultimately contribute anything useful to the search for the origins of life, it does push those questions farther back and allows people to have warm fuzzies about everything in the Universe being connected in a deeper sense than the fact we’re all products of the Big Bang, and I suspect that even atheists aren’t immune to finding such ideas appealing.

  18. robro says

    It all sounds like something someone would have babbled about over lunch…

    Based on my experience coming up with wild ideas, perhaps it was a well lubricated lunch. Or, a late night game of Hearts or Spades with their friends and lots of “things” to stimulate their imaginations.

  19. Bruce says

    Ruvkun is actually arguing AGAINST Earth life having come from Mars. He is saying both came from another solar system. Of course, this just makes his guess worse, as there is no evidence of rocks from other solar systems, unlike the evidence of Mars rocks. The Mars source idea is silly, but Ruvkun’s idea is much much worse than the Mars idea.

  20. nomdeplume says

    There are a subset of scientists in all disciplines who have realised that the path to fame and riches doesn’t lie in being the best scientist you can be and doing the best science you can, but in inventing some hare-brained idea that will attract the attention of the media because of its sheer wackiness. There is a similar group among politicians.

  21. says

    @Ray #4: It’s a fun idea and a “legitimate” theory, with no evidence and no real means of finding any to date. Any evidence would be located on Mars, and chances are we won’t find that until we get boots on the ground.
    But either way it’s completely useless as anything other than as a statement of fact if the evidence is found. It just doesn’t have predictive power except for the bloody obvious.

  22. williamhyde says

    Yes, that was a terrible article, part of a pattern in Salon lately. And the “just dumb” comment dishonestly ignores a horde of difficulties.

    We do know, however, that at least some Mars-Earth meteors do not get too hot for life to survive on entry to the Earth’s atmosphere. Such results were presented at AGU in 1997.

    Not being a biologist, I have no opinion on whether life could survive the years/decades in transit from Mars, and despite my lack of qualifications, I am enough of an arrogant physicist to be doubtful of its surviving the hundreds of thousands/millions of years in transit from another solar system.

    So, while I don’t think it’s likely, I am not quite ready to call it “just dumb”.

  23. unclefrogy says

    yah that is too irrational and removed from reality, too cherry picked, too perfect to make sense.
    If early life came from Mars and survived even the shortest trip to earth with all of the hazards and extremes that would include then we should easily find dormant if not active life still existing on Mars as well as every where else. Still waiting!


    blockquote>I’ve long thought that the final step from “not religious” to atheist is the toughest step for most people to make, and that even as many people are deserting Christianity and other organized religions, most still cling to that vague belief there is “something more” as a kind of spiritual security blanket.


    pardon me a moment here I agree and I could make the comparison with the story as I heard it of the Buddha sat under the Bodhi Tree he was assailed by a bunch of beings trying to get him to react his answer was to touch the ground of the immovable spot. The beings are those ideas we hold on to so dearly and the immovable spot is being with the realization that everything around is moving and we are but a temporary compilations of all that movement. there is nothing else at the same time as everything else.
    no father god or mother god or evil god no great story with us at the center there is no “immovable spot”
    If there is panspremia it will be us taking it all over which may happen but not yet at least.
    uncle frogy

  24. bcw bcw says

    One of the interesting questions about vent populations is where they come from since vent fields can be a long way apart and the sulfide foods the key bacteria live on is missing in the rest of the deep ocean. Nonetheless, when a new vent opens it is rapidly populated by the bacteria and all the things – tube worms, crabs, mollusks etc that live on it. Maybe they come from Mars…(right.)

  25. says

    @William #27: It’s not dumb at all, just pretty useless. It’s improbable for sure, but we can’t say it’s impossible. But so what? We were always going to search for life elsewhere anyhow, and we’re so ridiculously biased as to what constitutes life we are never going to miss a relative if we stumbled upon it on Mars.

    The only real point I can see is that research into abiogenesis should try to include conditions on early Mars as well. If there is any significant difference to begin with.

  26. chrislawson says

    Erlend Meyer@31–

    It would be an interesting exercise to do variations on the Miller-Urey experiment for early martian conditions. (I’m not aware of any specific martian efforts, there have been several variations run as models of earth’s early chemistry have waxed and waned.) But from a practical point of view, these experiments have already succeeded in showing that complex organic molecules will arise from simple molecules + energy, which is one of the key steps in abiogenesis. And we know a lot more than Miller did in 1952. For instance, that the Murchison meteorite contains complex organic molecules and that there are drifting clouds of amino acids in the interstellar medium, and these provide alternative lines of evidence for the M-U findings.

    The other step, yet to be experimentally observed, is the spontaneous rise of replicators. I don’t think anyone really knows how to calculate the probability of this event, or exactly what investigatory test to employ (worth knowing that Miller could only identify a small minority of the amino acids created in his experiment; researchers who went back and re-examined his samples with modern chemistry methods identified many more amino acids, including several that are not used by any known living organism). Which means it’s hard to know how long to run the experiment to have a decent chance of catching some replicators, and almost certainly impossible to run long enough to exclude the hypothesis of replicators emerging from a prebiotic soup.

    There are still some very interesting investigations that could be run with Miller-Urey variations, such as why earth life favours left-handed chirality, and what conditions would lead to amino acids spontaneously forming peptide chains.

    But with regards to abiogenesis, the next critical step is (imo) not likely to come from further Miller-Urey variations. (Note — this is not an argument against doing them! I’d be fascinated to see what we find.)

  27. whheydt says

    It’s not like at least the idea of panspermia is new. E. E. Smith used it as part of his background for a series of SF stories and novels he started writing in the 1930s, and doubt that he invented the idea or that it was new at the time.

    There is also that panspermia moves the problem of abiogenesis back one (or more) steps by claiming that it didn’t happen here, but it happen somewhere else.

  28. kurt1 says

    Like “the moonlanding was fake” people, I don’t get why they get so invested in this. There are absolutely no consequences, even if it were true.

  29. Kevin Karplus says

    I lean more towards David Deamer’s theory that life evolved in the margins of hot springs. He provides some pretty convincing ways that both protocells and RNA could have gotten started that the ocean-vent theory has a lot more trouble with.

  30. says

    I wish I had a better handle on what is holding me back here. I looked at that paper I linked to in 24 closer and I’m already carving into that area. The abstract mentions a protein complex that I’ve been reducing into protein subdomains along with nucleotide biosynthesis proteins and more.
    The Carbon Dioxide DeHydrogenase complex (CODH) is the more conserved (between bacteria and archea) branch of the pathway anaerobes use to make Acetyl-CoA, a universal cofactor used as a carbon (2 carbon acetyl) skeleton construction platform.
    I found things and spent pages drawing things several months ago. Shared subdomains and potential ancestral functions. But now it hurts to think about unless I happen to be able to answer a question. And that is one tangle out of several I’ve been trying to confront over the last several months.