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As Harrison noted, the authors are appropriately conservative.
The team found that the carbon trapped in a handful of rocks probed by the rover is dramatically enriched in light isotopes of carbon. On Earth, the signal would be seen as strong evidence for ancient microbial life...
...however, the researchers are reluctant to make any grand claims, and they have worked hard to concoct alternative, nonbiological explanations involving ultraviolet (UV) light and stardust. But those alternatives are at least as far-fetched as a scenario in which subterranean microbes emitted the enriched carbon as methane gas. The team concludes the study does “inch up the plausibility” that microbes once existed on the planet...
I'm curious if we do if we do find evidence for life on another planet would we explain it away with non-biological theoretical phenomenon before realizing its significance?
> if we do find evidence for life on another planet would we explain it away with non-biological theoretical phenomenon before realizing its significance?
Do you mean, will scientists carefully verify the accuracy of their claims? Would it be better if they shortcut that process when the question is exciting?
That's not what I mean at all. On Viking 2's LR experiment; "Our experiment was a definite positive response for life, but a lot of people have claimed that it was a false positive for a variety of reasons. One of the reasons was because there wasn't any water found"
We didn't even attempt to verify the accuracy of the LR experiment despite to-date nobody coming up with a non-biological explanation.
The DNA would be sequenced, compared to Earth's life forms, and if no relation is found then it should be explained. For me it would exponentially increase the probabilities of more life in the Universe.
If DNA is found, it almost certainly indicates a common ancestor. The likelihood of DNA evolving twice from whatever separate self-reproducing protolifeforms came before it has to be unbelievably low.
Everytime news like this comes up, I'm more certain that if we ever find life outside our planet, it would take years to be announced
I had the same thought after the phosphine gas discovery at Venus was announced. It will take so long to be certain about a claim like this, and evidence will mount so gradually, that by the time the confirmation is made it will be unsurprising. Sort of like the discovery of ancient liquid water on Mars - it took so long to prove it that by the time proof was certain, it had become a joke (NASA announces discovery of water on mars for Nth time! haha).
On the down side, we're less likely get a world-wide event to collectively celebrate; on the up side, we're less likely to panic subgroups of society.
Makes me think of how there is a huge hesitation to ever use the "F" word with any Mars photos. F - as in fossil.
There are definitely natural mineral formations that can mimic fossils, but then there are fossils too that aren't always obviously such.
Likely context of parent regarding fossils: https://en.wikipedia.org/wiki/Allan_Hills_84001
6 hours tops
And seconds to be destroyed.
It will be interesting to see if all life uses DNA in four pairs or if every planet evolves a system for encoding life differently.
My entirely uninformed guess is that life on Earth is probably fairly representative of how life forms on any similar planet. Throughout evolution there are endless ways life could have formed, and we're the product of whatever method worked best against billions or trillions or more possibilities. I wouldn't be surprised to find plants and animals on other planets that are not dissimilar to ones on Earth, especially considering the sheer number of types of animals and plants and how much they vary in structure and appearance.
It would be so exciting if they find life there
I'm glad they're careful not to oversell this finding, but it's a little discouraging how far we are from the phrase we want to hear:
"Mars has life"
"We've found past life on mars"
"Rover finds past life on mars"
"Rover finds hints of past life on mars"
"Rover detects hints of past life on mars"
"Rover detects carbon signature that hints of past life on mars"
"Rover detects carbon signature that may hint of past life on mars"
Not for me. Behind all those hedges is where the intrigue lies! I'd rather that than overselling a thrice-maybe as a positive.
You would have to look for evidence of life in the first place if you wanted to find it. None of the rovers we have on Mars right now have the right instruments to do so. Exomars' Rosalnd Franklin will be the first.
>"Rover detects carbon signature that may hint of past life on mars"
If you expand the list to include all the geological stuff Spirit/Oportunity, Pathfinder and Viking found then slap a "you are here" on it we are much closer to the "earth" end of things than the "dead rock" end of things.
I hope they don't. It would be a very bad indicator for our future in the cosmos, making it far more likely that whatever great filter is out there, is in front of us still.
Not necessarily. Before the great filter, there's the jump to multi-cellular life. As far as we know, the symbioses with mitochondria bacteria only happened once, and is the progenesis of all multi-cellular life on earth.
So single-celled life may not be terribly uncommon throughout the cosmos.
Isn't that backwards? The great filter is meant to explain why we don't see extraterrestrial life, so finding it would be counterevidence for a great filter
I don't think there's just one great filter.
I imagine there are various filters depending on the particular environment and circumstances.
Several are behind us already. Several are ahead.
This isn’t an original opinion, it’s taken from this paper:
it would be super ironic if it turned out earth life came from Mars or something :P
Beresheet Tardigrades floated over and are setting up camp to enact their revenge would be my bet.
Is anyone else having problem accessing the paper? The link on Science isn't working, and the DOI I managed to find in the rest of the coverage doesn't seem to exist. I can't find the paper anywhere.
Same. The reference appears to be "Depleted carbon isotope compositions observed at Gale crater, Mars, Proceedings of the National Academy of Sciences(2022). http://doi.org/10.1073/pnas.2115651119" DOI is not working yet but this is normal, however the link to PNAS seems broken indeed: https://www.pnas.org/content/119/4/e2115651119
I wonder - if you would build a dome over one of the water-ice-swamps in the canyons and allowed atmosphere to build up- if we would see something grow..
We are finding Mars originated rocks here, so it can be pieces of Earth on Mars too. Probability is low due to relatively thick Earth atmosphere, but still...
It astonishes me anew every time they land one of these things on Mars with exactly zero microscopes on board.
Thankfully the smart people of NASA listened
A microscope that cannot resolve smaller than 0.1 mm will not be very useful for seeing bacteria.
As it says in the blurb, "magnifying glass views".
SHERLOC/WATSON instruments on board Perseverance rover can image with 10-15um resolution. Not super impressive in terms of microscopy, but it's getting there.
Microscopes are expensive and you need to hire a martian to look at the samples. Last i looked on Linkedin there were not many martians with this qualification.
Don't we have microscopes that generate jpegs?
I heard that we had sent robots to Mars. (Some people don't believe that, but I do.) Some of these robots have been equipped to do a variety of sample preparations and science observations, and even to report some of their results back to Earth scientists.
"Damn it J355ie, i told you not to shit outside".
TLDR; "Still, the rover has seen no physical traces of ancient microbes"
Not a pro but AFAIK the threshold for anyone saying "yup we found life" would be very high and probably that the instruments currently deployed on Mars wouldn't possibly suffice to convince someone at NASA to make that call. That is, because (every?) experiments out there can be explained by a multitude of phenomenons that could be non-life based.
I wouldn't be surprised if life turns out to be abundant over there and we've just been very hard-nosed on the evidence we'll accept.
At least that's my understanding, when looking at summaries like https://www.youtube.com/watch?v=YwXSEP3_Rwk.
The problem is that there is so much noise regarding life on other planets (we found life on Venus, we found life on Mars ) that when we will really will be finding something will be something like "Another clickbaity title".
Or just the subtitle:
> Dramatically “light” carbon could also be explained by atmospheric reactions or cosmic dust
I dont think we would expect physical traces, but rather chemical traces.
Considering the 1996 "Life on Mars Hoax" was recently debunked, a bit of patience and caution would serve our planet.