4 ms·
Kind of bad news for human kind if we find out the life also started in Mars. One Great Filter down.
by 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 agoFor all we know, life started on Mars, not here. Hence the "sudden explosion" of life.
- vlovich123 1y agoI 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 agoneptune?
- vlovich123 1y agoSorry, I meant a moon of Neptune (Triton). There's also a recent research study suggesting Titan also has life.
- roncesvalles 1y agoIn 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 agoPanspermia 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.
- roncesvalles 1y agoI was never attempting to answer where life came from. It's simply that if Mars and Earth both have/had life, the probability that they came from some common cosmic seeding project in our neighborhood becomes a bit more likely.
- vlovich123 1y agoVs it’s a natural inevitable process when the conditions support it?
- vlovich123 1y agoWhere do the turtles start?
- d1sxeyes 1y agoIf that is true, then why does it seem that there has been only a single origin event on Earth?
- rrmm 1y agoDoes it seem that way? It happened at least once (but could have happened many times without "taking over"), and certainly one sort of life seemed to successfully out-compete all others. But none of that says single-origin to me. Early on I would expect a whole lot of "horizontal gene transfer" sort of things to have taken place. So for example in addition to actual horizontal gene transfer, there are mechanisms like one organism enveloping another to eventually become organelles, co-opting products from each other, etc. All of which would act to homogenize life and make certain process ubiquitous. Finally, there's an outside chance that "there's only one way to do it".
- roncesvalles 1y agoI think single origin event is highly likely because, for example, it's wholly conceivable that a slightly different variant of AUCG (or just one of the molecules) could've emerged and it would have similar characteristics, but not differentiated enough that one would have a very strong selective advantage over the other. Diversity could exist in harmony and the lack of any diversity is a pretty strong signal that the only extant version is either very rare or the only to ever emerge. Everything in nature is diverse except RNA/DNA and this fact alone is a sort of evidence.
- vlovich123 1y agoOr the basic life that forms is going to look the same regardless of where it starts on Earth, meaning that you’d never have evidence of two origins. Or RNA was just a winning virus that infected all other life or killed all competition to make it seem like there was only one origin. Absence of evidence is not evidence of absence.
- roncesvalles 1y ago
- aurareturn 1y ago"You start with a random clump of atoms, and if you shine light on it for long enough, it should not be so surprising that you get a plant." -Jeremy England Life increases entropy and doesn't break 2nd law of thermodynamics.
- mr_mitm 1y agoActually it's enough to have a sufficiently large amount of hydrogen. No extra light necessary.
- deleted 1y ago[deleted]
- elevaet 1y agoThey keep pushing back the date of the LUCA - I think it's meant to be 4.2 billion years ago now, a time when Mars was more nurturing than it is now, maybe moreso than Earth at the time? I hope we find out it started on Mars and jumped to Earth, how cool would that be?
- soiltype 1y agoI don't think there's any reasonable way to call that a likely scenario though. If life did emerge on Mars, why wouldn't it also emerge on Earth? For both planets to have life, the most likely explanation is that it's just common.
- 5tk18 1y agoWould you mind elaborating on this? I don’t understand the point. Maybe naively, I would think that evidence of life on mars would increase the probability of life on exoplanets.
- xg15 1y agoI guess the question is: If there was life on mars, what happened to it?
- maxbond 1y agoPresumably the planet became much less geologically active, causing Mars to lose it's magnetic field and thus it's atmosphere, and that caused a mass extinction. If there was life on the surface in the past, I imagine it still exists deep underground or in lava tubes or such.
- rrmm 1y agoI think the building blocks of life are so common in the universe it might be a case of "easy come, easy go". It wouldn't be surprising if simple life happened anywhere it was given half a chance at all, but one would equally expect that it would die out just as quickly when conditions changed (which they certainly did on Mars). And of course nothing is ruling out life in the nooks and crannies of Mars.
- empath75 1y agoThat actually isn't a hard question to answer. Mars lacks an active core or a magnetosphere, so the atmosphere blew away, freezing the surface and removing almost all of the liquid water.
- estimator7292 1y agoWe have proven that Mars used to have a magnetic field like Earth that protected it from solar radiation. We also know that it does not presently have a magnetic field. At some point in the distant past, Mars's core cooled and solidified, which removes the magnetic field. The big problem is that the solar wind strips away the atmosphere and water, but that's (probably) not what killed all Martian life. As the magnetic field decreases, more and more harmful radiation reaches the surface. The planet was probably sterilized by radiation long before the atmosphere was lost and the oceans evaporated. We're pretty sure this is what happened. We've been studying Mars's geology for a long time and we can see evidence for most of this process.
- JumpCrisscross 1y agoI think the filter was eukaryogenesis [1]. (Which in turn depends on the endosymbiosis of mitochondria.) Put simply, I expect the universe is littered with single-celled life. I think multicellular life, on the other hand, is rare. [1] https://en.m.wikipedia.org/wiki/Eukaryogenesis https://en.m.wikipedia.org/wiki/Eukaryogenesis
- Qem 1y ago> Which in turn depends on the endosymbiosis of mitochondria. Which in turn depends on existing enough atmospheric oxygen for mitochondria to make sense in first place. I believe the filter is atmospheric oxygen. If Earth had more iron in the crust, perhaps the cyanobacteria would never finish oxidizing all of it, and we would be doomed to only host microscopic life forever. Macroscopic life requires high-energy metabolism molecular oxygen allows.
- lawlessone 1y agoCould that be down to planet size? We have lots of iron , but most of it sank to the core during the "iron catastrophe" . And Mars is red because of theres so much iron.
- andrewflnr 1y agoEukaryogenesis != Multicellularity. There are tons of unicellular eukaryotes. Also, multicellularity has evolved a bunch of times, at least in eukaryotes, so I doubt it's that rare. If your thesis is specifically that oxygen-powered metabolism fueling multicellularity is rare... that wasn't clear. And I'll still say that endosymbiosis being the shortest path to scaling oxygen metabolism is probably Earth happenstance (with a reminder that cellular endosymbiosis is also common). But some critter had to originally evolve oxygen metabolism before being turned into mitochondria. What if that had evolved in a cell prepared to directly take advantage of it?
- JumpCrisscross 1y ago> There are tons of unicellular eukaryotes But no multicellular prokaryotes. You're right that eukaryotes can be single celled. But my hypothesis is that multicellular life is rare because eukaryotes are rare.
- estimator7292 1y agoIt's pretty unlikely that life emerged independently on two planets in adjoining orbits. The much more reasonable explanation is that life emerged on one planet and transferred over. Earth and Mars aren't particularly close, but they're close enough for material to transfer between them, particularly early in the solar system when there were far more asteroid impacts kicking rocks and dust out into space.
- pantalaimon 1y agoWhy would you say it's unlikely? For all we know simple life could emerge very easily if conditions are right and it's the step to complex life that's the hard one.
- tim333 1y agoIt would be very interesting to get a sample of life on Mars if there is some to see if they have the same chemistry or not.
- awesome_dude 1y agoMy hunch was completely the opposite Two planets in the "habitable zone" both receiving "ingredients" from the same stream of comets/meteors/cosmic dust, both with what we believe to be environments conducive to life (liquid water, surface temperatures/atmospheric pressures that aren't like Venus..:) In fact, I'm more surprised that life didn't start independently on both planets at roughly the same time (it could turn out that life did indeed start at the same time on both planets too, just it didn't "take hold" or "last as long" on Mars)
- Supermancho 1y agoAlternately, an impact to one world caused an upheaval that transferred the blocks to another. I do think the "galactic seeding" theory is more likely.
- deleted 1y ago[deleted]
- jordanb 1y agoThe inner planets have exchanged a lot of material it's possible they also exchanged life. In fact I believe some theories for how life formed rely on it.
- Bender 1y agoAnything is possible but unlikely we would find it unless there are buried megaliths signed by humans with graphic pictures. Even on Earth it would be hard to prove we were ever here after half a billion years after we destroy ourselves. It might not even take that long. Most things will rust, decompose, shatter into something resembling dust and many coastal regions will get recycled by plate techtonic movements. Mars has been a dead planet for a long time no magnetosphere, probably how this one will end up at some point.