The Daily Populous Thursday September 11st, 2025 day edition
Image from preview.redd.it and submitted by TheFleshGordon

hake2506 on September 10th, 2025 at 15:34 UTC »

NASA’s Mars rover Perseverance has uncovered rocks in a dry river channel that may hold potential signs of ancient microscopic life, scientists reported Wednesday.

https://www.wabi.tv/2025/09/10/new-findings-by-nasa-mars-rover-provide-strongest-hints-yet-potential-signs-ancient-life/

Morning_Song on September 10th, 2025 at 16:05 UTC »

Andromeda321 on September 10th, 2025 at 16:19 UTC »

Astronomer here! What an exciting day and intriguing result!

So, the first thing to note about looking for life is it's not like in the movies, where the saucer abruptly touches down and no one can argue aliens exist. In reality, it's a lot more complicated and we have to look for what are called biosignatures- things that, as far as we know, are only produced by life. The trouble is it's not as simple as "ah that only is produced by life, case closed!"- people can misidentify what the thing is (because science is hard, and a lot of molecules are very similar but not quite the same), and often signatures can be produced by life or non-life processes- what's more, it might be the case that on Earth only life produces a biosignature, but in a universe of options other mechanisms can create the biosignature.

So, in short, it's not as cut and dried as it is in a Hollywood movie to say "yes, I've found evidence of life!" Instead, a better way to think of it is water on Mars- when I was a kid, the idea of water on Mars was not at all thought to be true. But then one rover found some signature that indicated there might have been water, and another experiment found slightly more evidence... and today it's commonly accepted that Mars had giant liquid oceans in its past, and liquid water flows sometimes on the planet! This took years and years for scientists to find enough evidence to prove it, which is not as dramatic but is in line with the scientific process.

So with all that, today's result! Perserverence, a Mars rover, has found signatures of carbon-based compounds and minerals on rocks that, on Earth, are signs that microbial life exist- specifically, vivanite and greginite. (Full paper here!) SOMETIMES you can get these minerals created not because of microbial life, and the TL;DR of it all is from the rover data alone we can't figure out if the minerals are there because of microbial life interactions, or a non-life process. (This is outside my wheelhouse, but my understanding is more careful analysis of a rock in a lab on Earth, say, would tell you more about the formation of said rock and if microbes were involved.) So- big deal! First time we've found a solid potential biosignature, and arguably the best evidence so far that life used to exist on Mars! But not a smoking gun just yet to say "life on Mars!"

Finally, it's worth pointing out that right now as it stands the NASA planetary budget is going to be slashed so hard it's difficult to imagine we would be able to follow up on this, and the Perseverance rover itself for example is facing over a 20% cut on its budget. The deadline is the end of the month for the government to pass the continuing resolution that will include NASA/NSF/ everyone else who funds science, so please keep the pressure on with your Congressional reps!