I know how we can identify it
Scientists should remain skeptical if they study rock samples drilled by NASA’s Perseverance rover for evidence of alien life lest they be fooled by fake fossils, academics in the UK have warned. It’s difficult to find definitive signs of ancient microbial life in geological materials, Sean McMahon, an astrobiologist at the …
Is that a typo? Were they were using AI to speak and save it as text - did they say "Facebook News" and AI wrote Fake Ooze?
Given what we've seen on Mars it seems that the evolution of some form of life was a possibility but the current climate on Mars means that if any form of life exists then it's very unlikely to be like anything on Earth - maybe Mars just illustrates the effects of climate change 3 billion years ago?
One of the leading theories for the origin of life (panspermia) proposes that life arrived on earth and other planets as microbes from comets. That would give both Earth and Mars similar starting points for life, even if they then went in different directions, and there are also many observable phenomena (such as carcinization) that show us that life often evolves in similar directions, so life on Mars is likely to be not so different from life on Earth.
However, people who study this for a living (at least most of them) have plenty of thought into this. Probably more than those commenting here :D
Certainly, it's possible that when we are able to do some scientific work on Mars then we'll be able to see that this happened but the history of the planet has probably severely reduced the likelihood of an significant life on Mars - basic cellular life might exist but we see nothing that even indicates plants or even their fossils on the surface so far.
"but we see nothing that even indicates plants or even their fossils on the surface so far."
Although to be fair, we humans haven't closely examined very much at all of the Martian surface so far. Most of what we know has been observed from orbit. I'd love it if we found some evidence, but the odds are pretty low until there's some sort of long term human presence there.
Hear hear! Occam's razor is all too often left in the drawer when there's a chance to get your name in lights. (Cf the recent "discovery" of phosphine on Venus.)
As the authors imply, some form of abiotic self-organisation is a necessary precursor to life, but as we don't know what the path was on Earth let alone how many such paths might exist in general, there's going to be a lot of debate yet. For example it might be that life never quite got there on Mars, but left behind the dead ends of the process for us to find...
Incidentally, ideas about mineral structures being analogous or precursory to life aren't new. I used to have a little book by someone called LeDuc (can't find it now) from about 1916, who mixed various salt solutions in controlled ways to generate precipitates he considered to resemble fungi and other cells.
Yeah, there almost no evidence of what was around before plants started doing photosynthesis and produced such a large amount of highly toxic gas that changed the entire ecosystem of the planet, wiping out almost all the earlier forms of live. That bloody Oxygen was highly toxic to the early residents. And we worry about climate change? Here, I'll show you climate change!! :-)
Is interesting to compare change in climate due to GOE with modern one in fact. GOE change was cooling due to oxygen destroying methane in atmosphere (which without oxygen does not burn of course and is really serious GHG). Result was Huronian glaciation which may have included 'Snowball Earth' and oceans freezing solid (there is another much later event may have bee equally nasty).
So OK do the maths: say temperatures fell by 30 degrees (huge overestimate, so safe) and timescale of GOE was 100 million years (underestimate, so safe). This gives rate of change of 0.3 deg/My. Real rate probably much lower than this as deliberately overestimated swing and underestimated time.
Now compare us: say 1 degree rise (it is more) in 300 y (it is less): rate is 3 deg/ky: this is underestimate, deliberately.
So current warming rate is about 10,000 times higher than GOE cooling rate.
Obiously final swing in GOE caused change much larger than we will achieve, but if we were living through it before it got cold we would not probably be able to even detect the cooling it would be so slow.
How can you guestimate the timescale for s.t. that happened a billion years ago, and for which we've only recently even found evidence that it happened at all? In other words, how can you say 100 million years for the temp to drop is an underestimate? What's the evidence?
I am not expert in ancient atmosphere. But is safe to say that processes like this are generally slow. If methane theory is correct to explain early-faint-sun problem then you need enough oxygen to remove the methane after oxygenating the oceans and getting scavenged by all the other oxygen-removing processes, and this is a lot of oxygen, and that is likely slow. May be faster after ocean surface starts to freeze as albedo changes dramatically then.
So yes, is guess, perhaps expert will say.
Worth mentioning that other better-known events of non-anthropogenic climate change also are slow except where caused by catastrophic impact. For instance start of PETM was about 6K in 20ka or about 0.3mK/a, about a tenth of our warming rate (and much less than tenth in fact as I have assumed anthropogenic warming average over 300 years).
Much better information is available for recent glaciation / deglaciation events. Most recent deglaciation (so best data) took about 10ka (ended about 11.5ka ago), high-lattitude warming was about 10K (global average about 5K), giving 0.5mK/a to 1mK/a rate, still small fraction of current rate.
Is likely that the only things that ever have come near or exceeded current rate are impact events.
How about things actually moving around while the rover drives past?
and the two original pictures:
Now you see it....
Now you don't
Yeah, it is. The day is longer and has more than 24 hours in it, but the hour is still the same to a local observer. Nitpicking though, to an observer on Earth, it may be slightly different due to the difference in relative speed of Mars and Earth due to...err...relativity.
Mars timekeeping convention established during and after the Pathfinder missions adopted Martian hours, minutes and seconds as 2.75% longer than their Earth equivalents in order to avoid complex recalculations exceeding 23h59min59sec.
Martian Time of day
A convention used by spacecraft lander projects to date has been to enumerate local solar time using a 24-hour "Mars clock" on which the hours, minutes and seconds are 2.75% longer than their standard (Earth) durations.
This has the advantage that no handling of times greater than 23:59 is needed, so standard tools can be used. The Mars time of noon is 12:00 which is in Earth time 12 hours and 20 minutes after midnight.
Now you see it....
Now you don't
I see it in both photos.
Ah yes. Now you see here is what us scientists do when presented with this. First we observe that these two images were taken with different cameras: image with little green person (seems to be little black person, surely some mistake?) was taken with right mastcam-z camera, other image without small rock-climbing person was taken with left mastcam-z camera.
And amazing thing: we see little person again! And little person is at SAME PLACE IN IMAGE EACH TIME.
Now we use our science brains some more (probably we have several secret conferences funded by taxpayer at great expense), and we look at this image. This is second image from right mastcam-Z and first image which is not flat white, taken on sol 1. And LITTLE PERSON IS THERE! IN SAME PLACE!!!
Indeed after several minutes of exhaustive research (not at all done by our PhD-student-slaves, no), we conclude that little person is on EVERY right mastcam-z camera image after the flat white one, in same place.
What must we conclude? Another conference or two (our student-slaves are not invited other than the pretty ones). YES, WE HAVE IT.
LITTLE PERSON IS MARTIAN BACTERIUM, CLINGING TO SENSOR. WE HAVE FOUND LIFE ON MARS!!! FAME MONEY SEX DRUGS AWAIT!!!!.
Please to send Nobel prize to normal address. Thank you.
I completely agree with these chaps, but I unfortunately can't shake the feeling that the next sentence goes something along the lines of "We're in the process of developing a new lab to test these developments and would really love some money to make it happen. So give us some funding now and it will save you looking foolish later."
What we know from meteorites. Amino acids existed on Mars. Fossilized forms of life interactions (which are used in ancient Earth life studies) in meteorites resemble those found on Earth.
What we know from landers. Heated samples do not show complex chemistry like amino acids. But there is substantial evidence that heating samples releases perchlorate which breaks down complex compounds.
However, non-heated wet samples have found signs of metabolism (Viking Labeled Release (LR) experiment) and organic molecules (Curiosity wet chemistry experiment - the one that inspired this article).
We are left with a bunch of maybes. Occam's razor cuts both ways depending on your belief in the uniqueness of life on Earth.
It would seem to make sense that life is able capitalise on naturally occurring structures, and then propagate them once proven to have an evolutionary advantage.
The universe is full of enough variety and complexity to 'try anything at least once' so at the right time, when life comes a-knockin', the universe has already provided a home.
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