7 ms·

Minerals represent potential biosignatures in the search for life on Mars

130 points by stevenjgarner 1y ago

stevenjgarner 1y ago
“After a year of review, they have come back and they said, listen, we can’t find another explanation,” said Acting NASA Administrator Sean Duffy. “So this very well could be the clearest sign of life that we’ve ever found on Mars, which is incredibly exciting.” [1] [1] https://www.cnn.com/2025/09/10/science/nasa-mars-sapphire-falls-rock-sample https://www.cnn.com/2025/09/10/science/nasa-mars-sapphire-fa...
- pncnmnp 1y ago
  Some interesting stuff from the Nature paper > The Perseverance rover has explored and sampled igneous and sedimentary rocks within Jezero Crater to characterize early Martian geological processes and habitability and search for potential biosignatures ..... the organic-carbon-bearing mudstones in the Bright Angel formation contain submillimetre-scale nodules and millimetre-scale reaction fronts enriched in ferrous iron phosphate and sulfide minerals, likely vivianite and greigite, respectively. > Organic matter was detected in the Bright Angel area mudstone targets Cheyava Falls, Walhalla Glades and Apollo Temple by the SHERLOC instrument ..... A striking feature observed in the Cheyava Falls target (and the corresponding Sapphire Canyon core sample), is distinct spots (informally referred to as ‘leopard spots’ by the Mars 2020 Science Team) that have circular to crenulated dark-toned rims and lighter-toned cores > PIXL XRF analyses of reaction front rims reveal they are enriched in Fe, P and Zn relative to the mudstone they occur in ..... In the reaction front cores, a phase enriched in S-, Fe-, Ni- and Zn was detected > Given the potential challenges to the null hypothesis, we consider here an alternative biological pathway for the formation of authigenic nodules and reaction fronts. On Earth, vivianite nodules are known to form in fresh water ..... and marine ..... settings as a by-product of low-temperature microbially mediated Fe-reduction reactions. > In summary, our analysis leads us to conclude that the Bright Angel formation contains textures, chemical and mineral characteristics, and organic signatures that warrant consideration as ‘potential biosignatures’ that is, “a feature that is consistent with biological processes and that, when encountered, challenges the researcher to attribute it either to inanimate or to biological processes, compelling them to gather more data before reaching a conclusion as to the presence or absence of life ..... I had to look up PIXL XRF from this paper - https://arxiv.org/pdf/2402.01544 https://arxiv.org/pdf/2402.01544 - it is: > The Planetary Instrument for X-ray Lithochemistry (PIXL) is an X-ray fluorescence (XRF) spectrometer mounted on the arm of the National Aeronautics and Space Administration’s (NASA) Mars 2020 Perseverance rover (Allwood et al., 2020; Allwood et al., 2021). PIXL delivers a sub-millimeter focused, raster scannable X-ray beam, capable of determining the fine-scale distribution of elements in martian rock and regolith targets. PIXL was conceived following the work by Allwood et al. (2009) that demonstrated how micro-XRF elemental mapping could reveal the fine-textured chemistry of layered rock structures of ~3,450-million-year-old Archean stromatolitic fossils. Their work not only pushed back the accepted earliest possible window for the beginning of life on Earth, but also demonstrated that significant science return might be possible through XRF mapping. PIXL was proposed, selected, and developed to carry out petrologic exploration that provide the paleoenvironmental context required in the search for biosignatures on Mars, analogous to Allwood et al.’s earlier work.
  - awesome_dude 1y ago
    I like your analysis, but, personally, I am struggling with "Absence of data/other possibilities is pointing us to conclusion" It should (IMO) be reported as, we just don't know (yet), there's some really fascinating things that we cannot explain in any other way, yet, but that doesn't actually mean that we know for sure.
    - eightysixfour 1y ago
      I don't understand this critique at all. - We know this can happen through process A. - Really smart people have thought a lot about it and don't see other ways that it reasonably happened in this scenario. - This is pointing us to the conclusion that it happened through process A. Is a perfectly reasonable logic chain for a scientific paper and their conclusion literally says "we need more data." > compelling them to gather more data before reaching a conclusion as to the presence or absence of life”.
      - awesome_dude 1y ago
        What's not to understand - it's precisely the argument theists have put forward for millenia "We couldn't find anything to show it wasn't a god, so it must be a god" Calling one group "smart" doesn't change the process or the outcome - the absence of data is not data, it's just that we couldn't yet find the full explanation. One day we might, it might actually be life, but we don't have that right now, so, actual science demands that we withhold any wild speculation.
        tim333 1y ago
        "- We know this can happen through process A." doesn't really apply to theism. "We know worlds can be created by gods" was never really a thing.
        awesome_dude 1y ago
        We don't actually know. We suspect that it's rubbish, but we don't have enough evidence to conclusively say one way or another.
- pklausler 1y ago
  [flagged]
  - galacticaactual 1y ago
    [flagged]
aurareturn 1y ago
Kind of bad news for human kind if we find out the life also started in Mars. One Great Filter down.
- withinboredom 1y ago
  For all we know, life started on Mars, not here. Hence the "sudden explosion" of life.
  - vlovich123 1y ago
    I prefer the theory that life is the natural evolution of physical chemical processes given certain conditions. That explains why we think that we’re likely to find life on Neptune. Otherwise it begs the question of why did life start on Mars, and that’s a turtles all the way down kind of situation.
    - lawlessone 1y ago
      neptune?
      - vlovich123 1y ago
        Sorry, I meant a moon of Neptune (Triton). There's also a recent research study suggesting Titan also has life.
    - roncesvalles 1y ago
      In addition to one seeding the other, neighboring planets having life also gives support to extra-solar-system panspermia. An advanced civilization could've fired off the "seed" in some vehicles on calculated trajectories to all viable planets, and the Solar System happened to be within the radius of their efforts.
      - estimator7292 1y ago
        Panspermia is such a juvenile take. It doesn't answer the question at all, just hand-waves it all away with a "because I said so". It's like a religion.
treis 1y ago
Still seems fairly speculative to me. I think it's very likely that there was life given all the water but this is still a ways away from a smoking gun.
- zokier 1y ago
  Smoking gun needs sample return, and the current outlook for that mission is not great.
- rrmm 1y ago
  You are right: this is indeed no smoking gun (and it isn't hyped to be one). This is more like "we can't rule out life having created this, but there are alternate explanations which have also not been ruled out". Unfortunately most of the evidence is going to be like this. The chances for better evidence would probably require a sample return of some sort, and even then I wouldn't expect a smoking gun (either way).
  - andrewflnr 1y ago
    Well, not exactly. By my read, the known alternate explanations are very strained, only there for propriety. They don't have a really clear idea how this could have formed abiotically.
lawlessone 1y ago
Is this like a banded iron formation?
- eigenform 1y ago
  Similar idea I think: organics depositing iron
zokier 1y ago
Just as a side note, this rock has been garnering lot of interest pretty much immediately as it was discovered a year ago. There were also few papers published this spring hinting at biological origin. https://edition.cnn.com/2024/07/26/science/nasa-perseverance-rover-cheyava-falls-rock https://edition.cnn.com/2024/07/26/science/nasa-perseverance... https://earthsky.org/space/life-on-mars-leopard-spots-poppy-seeds-perseverance-rover/ https://earthsky.org/space/life-on-mars-leopard-spots-poppy-... So if you feel like you heard this story before, then it's probably one of the previous times this rock made the rounds
- stevenjgarner 1y ago
  I think the notable thing this time is Acting NASA Administrator Sean Duffy referring to the (current) Sep 10th Nature paper by summarizing that “After a year of review, they have come back and they said, listen, we can’t find another explanation, so this very well could be the clearest sign of life that we’ve ever found on Mars, which is incredibly exciting.”
jenadine 1y ago
> Clearest sign' yet of ancient life on Mars Is it more clear than the presence of artificial canals on the planet? Because at the time, the signs were quite clear as well. https://en.wikipedia.org/wiki/Martian_canals https://en.wikipedia.org/wiki/Martian_canals
- JumpCrisscross 1y ago
  > Is it more clear than the presence of artificial canals on the planet? …yes. Exhibit A is TFA. Exhibit B is the claim that there is ancient life has a lower burden of proof than that there was an ancient technological civilization.
- turtletontine 1y ago
  This is a silly comparison. The article itself does not contain any phrase like "Clearest Sign Yet of Ancient Life on Mars", it was someone else's decision to give it the clickbait title here. I'm not an expert on the topic here, but at arm's length this sure seems like responsible scientists doing their best to rigorously study something with some crazy implications. They're not saying "OMG guys there was life on mars!!!!", they're saying from what we can tell with Perseverance's little portable lab these rocks sure seem consistent with a biosignature. Their conclusion is that gee it would be great to have samples brought back to earth for better analysis, which... maybe one day, who knows? Here's what they actually say: Ultimately, we conclude that analysis of the core sample collected from this unit using high-sensitivity instrumentation on Earth will enable the measurements required to determine the origin of the minerals, organics and textures it contains.
  - stevenjgarner 1y ago
    > it was someone else's decision to give it the clickbait title here Is it notable that the "someone else" is Acting NASA Administrator Sean Duffy referring to the publication with “After a year of review, they have come back and they said, listen, we can’t find another explanation, so this very well could be the clearest sign of life that we’ve ever found on Mars"?
PowerWordPoint 1y ago
[dead]
kjkjadksj 1y ago
I’ve read that NASA has chosen landing sites that specifically have evidence of ancient rather than more recent or even present day water, with the logic that they do not want to potentially contaminate a site with active martian life with earth based microbes. Can anyone speak more towards this or identify some of these potential sites that harbor life on mars? Will we ever directly probe somewhere that likely harbors life?
- JumpCrisscross 1y ago
  > NASA has chosen landing sites that specifically have evidence of ancient rather than more recent or even present day water Source?
  - kjkjadksj 1y ago
    https://nap.nationalacademies.org/read/11937/chapter/9 https://nap.nationalacademies.org/read/11937/chapter/9
- lawlessone 1y ago
  >Will we ever directly probe somewhere that likely harbors life I recall a few years ago when they believed they had seen liquid water running down a hill they didn't want to move a probe near it for fear of contaminating it.
mrtksn 1y ago
What happened with the organic gases in the upper atmosphere of Venus? I would love it if we find that the life in the universe is ubiquitous. I'm inclined to believe that this should be the case anyway.
- tim333 1y ago
  Theories of the origin of life on earth seem to be leaning towards it happening on/in warm damp rocks where RNA like molecules can accumulate in pores. I think there would be problems on Venus - the rocks are too hot, nothing cell like in the atmosphere. But it may be common with a warm damp rock set up which probably was there on Mars. Organic molecules are fairly common in the solar system on asteroids and the like and probably of non biological origins.
  - andrewflnr 1y ago
    I think the idea with Venus is that life in the atmosphere was a leftover from a more habitable period.
- andrewflnr 1y ago
  Last I heard there was a lot of back and forth about whether that was a real signal. I guess phosphine is easy to mistake for SO2, which, well, Venus has a lot of SO2.
Qem 1y ago
Related comics: https://www.badspacecomics.com/post/apostles-of-mercy https://www.badspacecomics.com/post/apostles-of-mercy If we eventually find martian microbes, or at least their fossils, my bet is that we'll find them to be related to us.
- feoren 1y ago
  I'm always amused when sci-fi writers think they're being deep by having ancient humans be aliens from another planet. They just completely forget about the 10 million other species we're so clearly related to? Ancient bacteria on meteorites might explain why DNA looks the same, but it doesn't explain the steady, continuously increasing genetic difference between us and our increasingly distant cousin species. It doesn't explain the dozens of "missing link" fossils between modern humans and ancient primates. If ancient humans came from another planet, then they must have brought billions of other lifeforms from millions of different species with them as well, including millions of fossils that they then buried at the appropriate strata as some sort of prank on future paleontologists, on a giant ark that has completely disappeared. It's such a weak take. The natural record is far too clear for that to make any sense. Now, Mars / Earth cross-seeding proto-bacteria, billions of years ago, sure. Of course the energy required to kick up a rock to a trajectory where it will hit Mars (or vice versa) is orders of magnitude more than the energy required to vaporize all nearby life, so we've got a pretty big problem already. More likely, they both got seeded when our solar system passed through a cloud of primitive organic proto-life (this is my favorite theory). But eukaryotic transfer? Multi-cellular life transferring between the two worlds? No.
  - tim333 1y ago
    >the energy required to kick up a rock to a trajectory where it will hit Mars (or vice versa) is orders of magnitude more than the energy required to vaporize all nearby life, so we've got a pretty big problem already Not necessarily. Something like the asteroid that killed the dinosaurs would have created temperatures at the impact point high enough to vapourize everything but probably also chucked a lot of more distant stuff into the sky that didn't get as hot. Here's a Discovery channel 'simulation' of a large impact chucking stuff up https://youtu.be/bU1QPtOZQZU?t=67 https://youtu.be/bU1QPtOZQZU?t=67 Not sure it's very accurate but it gives an impression of the sort of thing that may have happened.
deleted 1y ago
[deleted]
stevenjgarner 1y ago
NASA Sharing Details of New Perseverance Mars Rover Finding [Video] https://youtu.be/-StZggK4hhA?t=1041 https://youtu.be/-StZggK4hhA?t=1041 (see https://news.ycombinator.com/edit?id=45205855 https://news.ycombinator.com/edit?id=45205855)

130 points by stevenjgarner 1y ago

“After a year of review, they have come back and they said, listen, we can’t find another explanation,” said Acting NASA Administrator Sean Duffy. “So this very well could be the clearest sign of life that we’ve ever found on Mars, which is incredibly exciting.” [1] [1] https://www.cnn.com/2025/09/10/science/nasa-mars-sapphire-falls-rock-sample https://www.cnn.com/2025/09/10/science/nasa-mars-sapphire-fa...

pncnmnp 1y ago
Some interesting stuff from the Nature paper > The Perseverance rover has explored and sampled igneous and sedimentary rocks within Jezero Crater to characterize early Martian geological processes and habitability and search for potential biosignatures ..... the organic-carbon-bearing mudstones in the Bright Angel formation contain submillimetre-scale nodules and millimetre-scale reaction fronts enriched in ferrous iron phosphate and sulfide minerals, likely vivianite and greigite, respectively. > Organic matter was detected in the Bright Angel area mudstone targets Cheyava Falls, Walhalla Glades and Apollo Temple by the SHERLOC instrument ..... A striking feature observed in the Cheyava Falls target (and the corresponding Sapphire Canyon core sample), is distinct spots (informally referred to as ‘leopard spots’ by the Mars 2020 Science Team) that have circular to crenulated dark-toned rims and lighter-toned cores > PIXL XRF analyses of reaction front rims reveal they are enriched in Fe, P and Zn relative to the mudstone they occur in ..... In the reaction front cores, a phase enriched in S-, Fe-, Ni- and Zn was detected > Given the potential challenges to the null hypothesis, we consider here an alternative biological pathway for the formation of authigenic nodules and reaction fronts. On Earth, vivianite nodules are known to form in fresh water ..... and marine ..... settings as a by-product of low-temperature microbially mediated Fe-reduction reactions. > In summary, our analysis leads us to conclude that the Bright Angel formation contains textures, chemical and mineral characteristics, and organic signatures that warrant consideration as ‘potential biosignatures’ that is, “a feature that is consistent with biological processes and that, when encountered, challenges the researcher to attribute it either to inanimate or to biological processes, compelling them to gather more data before reaching a conclusion as to the presence or absence of life ..... I had to look up PIXL XRF from this paper - https://arxiv.org/pdf/2402.01544 https://arxiv.org/pdf/2402.01544 - it is: > The Planetary Instrument for X-ray Lithochemistry (PIXL) is an X-ray fluorescence (XRF) spectrometer mounted on the arm of the National Aeronautics and Space Administration’s (NASA) Mars 2020 Perseverance rover (Allwood et al., 2020; Allwood et al., 2021). PIXL delivers a sub-millimeter focused, raster scannable X-ray beam, capable of determining the fine-scale distribution of elements in martian rock and regolith targets. PIXL was conceived following the work by Allwood et al. (2009) that demonstrated how micro-XRF elemental mapping could reveal the fine-textured chemistry of layered rock structures of ~3,450-million-year-old Archean stromatolitic fossils. Their work not only pushed back the accepted earliest possible window for the beginning of life on Earth, but also demonstrated that significant science return might be possible through XRF mapping. PIXL was proposed, selected, and developed to carry out petrologic exploration that provide the paleoenvironmental context required in the search for biosignatures on Mars, analogous to Allwood et al.’s earlier work.
- awesome_dude 1y ago
  I like your analysis, but, personally, I am struggling with "Absence of data/other possibilities is pointing us to conclusion" It should (IMO) be reported as, we just don't know (yet), there's some really fascinating things that we cannot explain in any other way, yet, but that doesn't actually mean that we know for sure.
  - eightysixfour 1y ago
    I don't understand this critique at all. - We know this can happen through process A. - Really smart people have thought a lot about it and don't see other ways that it reasonably happened in this scenario. - This is pointing us to the conclusion that it happened through process A. Is a perfectly reasonable logic chain for a scientific paper and their conclusion literally says "we need more data." > compelling them to gather more data before reaching a conclusion as to the presence or absence of life”.
    - awesome_dude 1y ago
      What's not to understand - it's precisely the argument theists have put forward for millenia "We couldn't find anything to show it wasn't a god, so it must be a god" Calling one group "smart" doesn't change the process or the outcome - the absence of data is not data, it's just that we couldn't yet find the full explanation. One day we might, it might actually be life, but we don't have that right now, so, actual science demands that we withhold any wild speculation.
      - tim333 1y ago
        "- We know this can happen through process A." doesn't really apply to theism. "We know worlds can be created by gods" was never really a thing.
        awesome_dude 1y ago
        We don't actually know. We suspect that it's rubbish, but we don't have enough evidence to conclusively say one way or another.
pklausler 1y ago
[flagged]
- galacticaactual 1y ago
  [flagged]

aurareturn 1y ago

Kind of bad news for human kind if we find out the life also started in Mars. One Great Filter down.

withinboredom 1y ago
For all we know, life started on Mars, not here. Hence the "sudden explosion" of life.
- vlovich123 1y ago
  I prefer the theory that life is the natural evolution of physical chemical processes given certain conditions. That explains why we think that we’re likely to find life on Neptune. Otherwise it begs the question of why did life start on Mars, and that’s a turtles all the way down kind of situation.
  - lawlessone 1y ago
    neptune?
    - vlovich123 1y ago
      Sorry, I meant a moon of Neptune (Triton). There's also a recent research study suggesting Titan also has life.
  - roncesvalles 1y ago
    In addition to one seeding the other, neighboring planets having life also gives support to extra-solar-system panspermia. An advanced civilization could've fired off the "seed" in some vehicles on calculated trajectories to all viable planets, and the Solar System happened to be within the radius of their efforts.
    - estimator7292 1y ago
      Panspermia is such a juvenile take. It doesn't answer the question at all, just hand-waves it all away with a "because I said so". It's like a religion.

treis 1y ago

Still seems fairly speculative to me. I think it's very likely that there was life given all the water but this is still a ways away from a smoking gun.

zokier 1y ago
Smoking gun needs sample return, and the current outlook for that mission is not great.
rrmm 1y ago
You are right: this is indeed no smoking gun (and it isn't hyped to be one). This is more like "we can't rule out life having created this, but there are alternate explanations which have also not been ruled out". Unfortunately most of the evidence is going to be like this. The chances for better evidence would probably require a sample return of some sort, and even then I wouldn't expect a smoking gun (either way).
- andrewflnr 1y ago
  Well, not exactly. By my read, the known alternate explanations are very strained, only there for propriety. They don't have a really clear idea how this could have formed abiotically.

lawlessone 1y ago

Is this like a banded iron formation?

eigenform 1y ago
Similar idea I think: organics depositing iron

zokier 1y ago

Just as a side note, this rock has been garnering lot of interest pretty much immediately as it was discovered a year ago. There were also few papers published this spring hinting at biological origin. https://edition.cnn.com/2024/07/26/science/nasa-perseverance-rover-cheyava-falls-rock https://edition.cnn.com/2024/07/26/science/nasa-perseverance... https://earthsky.org/space/life-on-mars-leopard-spots-poppy-seeds-perseverance-rover/ https://earthsky.org/space/life-on-mars-leopard-spots-poppy-... So if you feel like you heard this story before, then it's probably one of the previous times this rock made the rounds

stevenjgarner 1y ago
I think the notable thing this time is Acting NASA Administrator Sean Duffy referring to the (current) Sep 10th Nature paper by summarizing that “After a year of review, they have come back and they said, listen, we can’t find another explanation, so this very well could be the clearest sign of life that we’ve ever found on Mars, which is incredibly exciting.”

jenadine 1y ago

> Clearest sign' yet of ancient life on Mars Is it more clear than the presence of artificial canals on the planet? Because at the time, the signs were quite clear as well. https://en.wikipedia.org/wiki/Martian_canals https://en.wikipedia.org/wiki/Martian_canals

JumpCrisscross 1y ago
> Is it more clear than the presence of artificial canals on the planet? …yes. Exhibit A is TFA. Exhibit B is the claim that there is ancient life has a lower burden of proof than that there was an ancient technological civilization.
turtletontine 1y ago
This is a silly comparison. The article itself does not contain any phrase like "Clearest Sign Yet of Ancient Life on Mars", it was someone else's decision to give it the clickbait title here. I'm not an expert on the topic here, but at arm's length this sure seems like responsible scientists doing their best to rigorously study something with some crazy implications. They're not saying "OMG guys there was life on mars!!!!", they're saying from what we can tell with Perseverance's little portable lab these rocks sure seem consistent with a biosignature. Their conclusion is that gee it would be great to have samples brought back to earth for better analysis, which... maybe one day, who knows? Here's what they actually say: Ultimately, we conclude that analysis of the core sample collected from this unit using high-sensitivity instrumentation on Earth will enable the measurements required to determine the origin of the minerals, organics and textures it contains.
- stevenjgarner 1y ago
  > it was someone else's decision to give it the clickbait title here Is it notable that the "someone else" is Acting NASA Administrator Sean Duffy referring to the publication with “After a year of review, they have come back and they said, listen, we can’t find another explanation, so this very well could be the clearest sign of life that we’ve ever found on Mars"?

PowerWordPoint 1y ago

[dead]

kjkjadksj 1y ago

I’ve read that NASA has chosen landing sites that specifically have evidence of ancient rather than more recent or even present day water, with the logic that they do not want to potentially contaminate a site with active martian life with earth based microbes. Can anyone speak more towards this or identify some of these potential sites that harbor life on mars? Will we ever directly probe somewhere that likely harbors life?

JumpCrisscross 1y ago
> NASA has chosen landing sites that specifically have evidence of ancient rather than more recent or even present day water Source?
- kjkjadksj 1y ago
  https://nap.nationalacademies.org/read/11937/chapter/9 https://nap.nationalacademies.org/read/11937/chapter/9
lawlessone 1y ago
>Will we ever directly probe somewhere that likely harbors life I recall a few years ago when they believed they had seen liquid water running down a hill they didn't want to move a probe near it for fear of contaminating it.

mrtksn 1y ago

What happened with the organic gases in the upper atmosphere of Venus? I would love it if we find that the life in the universe is ubiquitous. I'm inclined to believe that this should be the case anyway.

tim333 1y ago
Theories of the origin of life on earth seem to be leaning towards it happening on/in warm damp rocks where RNA like molecules can accumulate in pores. I think there would be problems on Venus - the rocks are too hot, nothing cell like in the atmosphere. But it may be common with a warm damp rock set up which probably was there on Mars. Organic molecules are fairly common in the solar system on asteroids and the like and probably of non biological origins.
- andrewflnr 1y ago
  I think the idea with Venus is that life in the atmosphere was a leftover from a more habitable period.
andrewflnr 1y ago
Last I heard there was a lot of back and forth about whether that was a real signal. I guess phosphine is easy to mistake for SO2, which, well, Venus has a lot of SO2.

Qem 1y ago

Related comics: https://www.badspacecomics.com/post/apostles-of-mercy https://www.badspacecomics.com/post/apostles-of-mercy If we eventually find martian microbes, or at least their fossils, my bet is that we'll find them to be related to us.

feoren 1y ago
I'm always amused when sci-fi writers think they're being deep by having ancient humans be aliens from another planet. They just completely forget about the 10 million other species we're so clearly related to? Ancient bacteria on meteorites might explain why DNA looks the same, but it doesn't explain the steady, continuously increasing genetic difference between us and our increasingly distant cousin species. It doesn't explain the dozens of "missing link" fossils between modern humans and ancient primates. If ancient humans came from another planet, then they must have brought billions of other lifeforms from millions of different species with them as well, including millions of fossils that they then buried at the appropriate strata as some sort of prank on future paleontologists, on a giant ark that has completely disappeared. It's such a weak take. The natural record is far too clear for that to make any sense. Now, Mars / Earth cross-seeding proto-bacteria, billions of years ago, sure. Of course the energy required to kick up a rock to a trajectory where it will hit Mars (or vice versa) is orders of magnitude more than the energy required to vaporize all nearby life, so we've got a pretty big problem already. More likely, they both got seeded when our solar system passed through a cloud of primitive organic proto-life (this is my favorite theory). But eukaryotic transfer? Multi-cellular life transferring between the two worlds? No.
- tim333 1y ago
  >the energy required to kick up a rock to a trajectory where it will hit Mars (or vice versa) is orders of magnitude more than the energy required to vaporize all nearby life, so we've got a pretty big problem already Not necessarily. Something like the asteroid that killed the dinosaurs would have created temperatures at the impact point high enough to vapourize everything but probably also chucked a lot of more distant stuff into the sky that didn't get as hot. Here's a Discovery channel 'simulation' of a large impact chucking stuff up https://youtu.be/bU1QPtOZQZU?t=67 https://youtu.be/bU1QPtOZQZU?t=67 Not sure it's very accurate but it gives an impression of the sort of thing that may have happened.

deleted 1y ago

[deleted]

stevenjgarner 1y ago

NASA Sharing Details of New Perseverance Mars Rover Finding [Video] https://youtu.be/-StZggK4hhA?t=1041 https://youtu.be/-StZggK4hhA?t=1041 (see https://news.ycombinator.com/edit?id=45205855 https://news.ycombinator.com/edit?id=45205855)