Methane in Earth’s atmosphere mostly come from cow farts.
Methane in other atmospheres, as far as we know, doesn’t come from alien cow farts.
There’s a bunch of stuff that’s made by life, but it can also be made by not-life.
Comment on Searching for signs of life on exoplanets is tough.
danc4498@lemmy.world 2 days ago
Please explain. I’m way too stupid.
crunchy@lemmy.dbzer0.com 2 days ago
Diplomjodler3@lemmy.world 2 days ago
I believe the alien cow fart theory!
AngryCommieKender@lemmy.world 2 days ago
Burps primarily as far as the cows are concerned.
StalinIsMaiWaifu@lemmygrad.ml 2 days ago
Biosignature- signs that life was present
Abiotic exponation- any explanation that doesn’t require life
Exoplanet- planet outside the solar system
Telescopes pick up light from these planets, we then analyse the light to see what elements/compounds make up their atmosphere. Say there’s a planet which has a noticeable increase in atmospheric carbon, the scientist in the meme is tempted to say it’s evidence of life (Forrest fire, industrialization, respiration), but it could be a geological process (volcanic eruption)
chosensilence@pawb.social 2 days ago
my guess: there is an exoplanet, K2-18b, that was discovered to have an abundance of detectable biosignatures in its atmosphere. at the time, there wasn’t much in the way of another explanation that didn’t involve life. however, astronomers recently found a failed star that is filled with biosignature molecules… so… ah lol. now perhaps K2-18b has another explanation after all.
danc4498@lemmy.world 2 days ago
So much Astronomy drama!
Legianus@programming.dev 1 day ago
Astronomer here, the “life detection” on K2-18b was dimethyl sulfide (DMS) and which is and remains a marker for life. What you get from the James Webb Space Telescope (JWST) is raw data that needs to be treated and calibrated to some extent to be usable in scientific study. This is called data retrieval.
However, the lead scientist on this paper claiming they found DMS basically used his own very specific way to do it and found very very weak signals in that way. Other scientist tried to both reproduce it in the way he did it and also with their ways to retrieve the data, but couldn’t find anything. So it turns out, it was simply a misdetection.
chosensilence@pawb.social 19 hours ago
also, may i ask a question? you say “is and remains” a marker for life. i am not well read about these things, is that because DMS is only observed as a biosignature here on Earth, or are you saying it couldn’t possibly have a nonbiological origin?
Legianus@programming.dev 19 hours ago
Sure. Generally, it is a marker for life as we see it being produced by living organisms on Earth and it also should vanish quickly from atmospheres if it is not replenished. However, as you correctly put it, there may always be a non-biological explanation as well for any of these marker. So far I know, DMS has no non-biological explanation so far and is seen as a biological marker still.
Alas, the possibility of it being proven non-biological or even (as happend here) not a real detection makes it even more important to get more data and be very careful about the statements made from it than as otherwise those statements and/or connected papers have to be corrected/retracted.
chosensilence@pawb.social 20 hours ago
oh hey, wonderful. thank you!
Buddahriffic@lemmy.world 2 days ago
Would be funny if that failed star was actually an alien megaproject but we think it’s a natural explanation that means a planet teeming with ancient life is assumed to be barren like the rest of them.
Is there a name for that, when something very interesting is mistaken for something very uninteresting? Not that a failed star full of biosignature molecules sounds uninteresting, do they have any explanation for that?
HonoraryMancunian@lemmy.world 2 days ago
John Michael Godier will be disappointed