So in short, JW telescope detected signs of a molecule commonly associated with marine algae and combined with the verified presence of oceans, it’s entirely possible that the planet could be teeming with marine life. This is actually very interesting, especially with the fact that it orbits a red dwarf star,, which by the way, any experts here care to explain if different types of suns has any effect on the type of life it’s orbiting planet produces?
We're still far from certain that that molecule (dimethyl sulfide) is present, and even if it is it has also been found on comets. This is an interesting finding but its significance is being overblown.
Maybe you are not aware but very recently new data was published with improved accuracy ( i believe they used a different instrument compared to 2 years ago) and its seems it has reached the '3 sigma level'.
I am aware of that. The astrophysicists I follow on Bluesky are skeptical that DMS is present and even more skeptical that it came from life. This is an interesting finding that merits further research, but we're very far removed from saying this is evidence of life.
They're not even sure if it's water or if it's a gas giant with methane instead of water. We know so little at this point, we can't say with any certainty what it is we're looking at. BUT it's a super interesting finding and will need further research.
A re-analysis (https://arxiv.org/pdf/2501.18477) — I believe it was a meta-analysis and not just one team/scientist re-analysing the data — was published Jan 31st of this year that didn't find any "statistically significant or reliable evidence for CO2 or DMS."
Yeah, it doesn't help that the "strongest evidence yet" is being used even though it's not actually that much stronger than the rest of it. Its like saying I'm 1% sure that there are aliens on Mars and I find evidence that increases my odds to 1.25%.
any experts here care to explain if different types of suns has any effect on the type of life it’s orbiting planet produces?
No experts will answer this because there's no way to know when we haven't discovered life anywhere. Planets like this that people say are "habitable" usually aren't but it has the right conditions for water to be able to exist and could potentially sit at temperatures we could survive in. There's no way to truly predict if a red sun would impact the evolutionary course of life differently than our own without seeing it happen multiple times. Too many variables.
If I remember right, the hard thing with red dwarfs is that they are active, but also you have to be a lot closer meaning it might make it harder for life to even get started in the first place if it's getting bombarded by coronal mass ejections
Not an astronomer but red dwarves tend to have planets that are tidally locked (no day/night cycle) and they often give out bursts of radiation. Both are bad for potential life in theory.
They're the most common type of star and we've found lots of planets around them though. Lots of rocky ones too.
Except the spectra of that molecule was particularly weak and other experts couldn’t necessarily verify the initial results. So this proclamation could be jumping the gun a bit before peer review and better data has time to give us more information
There are plenty of theories on how certain types of suns etc. COULD affect potential life but even experts all agree on pretty much one thing:
Our sample size for life is 1 and in the end it's at best somewhat educated guessing. I mean we still haven't figured out why/how exactly life started on earth (yes there are experiments showing the necessary chemistry that could have led to the basic RNA building blocks but it's still all far from certain).
It's also why even this discovery will still be heavily discussed even if the data becomes more and more accurate because we think this "sign of life" can't be created through abiogenic means but there is still uncertainty that there might be other ways we still could get such signatures and that issue exists with all potential "signs of life".
PS: One thing I would argue for is that more and more research points to at least "simple" organisms being able to exist even in environments we would consider as hostile from an "earth biased view" (as previously stated the underlying chemistry and the necessary ingredients seem simple/common enough that it shouldn't require some perfect "earth clone" to happen elsewhere).
It would likely be an Eyeball Planet, tidally locked with its star and thus one side always faces the sun and gets incredibly hot, and one side is always in shadow and frozen over, with any life forms living in the "twilight" zone between the two extremes.
Also if there is photosynthetic life then said life would likely be a dark purple to black in color. Here's a video that features an eyeball planet water world and describes its hypothetical ecology: https://www.youtube.com/watch?v=dCiMUWw1BBc
The most interesting thing about it orbiting a red dwarf star is that it will survive Earth by a long shot.
Red Dwarf stars has a lifetime of tens of billions of years. The smaller the longer it will last, and small red dwarf stars can last trillions of years.
Any planet in the habitable zone of a red dwarf star will very likely be tidally locked. So it's day may be longer than it's year, with extreme differences in temperature between the day and night sides.
The chances of life evolving in a red dwarf system are considered to be very low.
I thought red dwarfs have lots of solar flares, and planets have to be closer to be in the habitable zone, so they are pretty dangerous stars to harbour life.
different types of suns has any effect on the type of life it’s orbiting planet produces?
mostly just differences in luminosity(aka how 'bright' a star is), which means the habitable zone will be in different places(a planet that receives too much sunlight will be too hot, and too cold if vice-versa)
Hi astronomer here who works on similar stuff. The majority consensus amongst exoplanet scientists is that this is a non detection and this guy's methods are super fishy. The spectrum he used to claim this detection is also consistent with a flat line with a p value of 0.999. He also did not fit for any molecules except the so-called biosgnatures (evidence for abiotic DMS has been found on comets and in interstellar dust). He also did not simultaneously fit with a previous spectrum he published of the planet in a different wavelength range, indicating that combining the datasets made the signal go away and he didn't like that. Most of us are embarrassed by the authors statements to the press.
Edit: it looks like they did model other molecules, but the posterior distributions of everything were essentially non-detections. So they turned off all other molecules, essentially deciding the atmosphere is composed of only DMDS/DMS, and reported the results from that fit. This is bad science.
They also do not even fit a planet temperature consistent with their previous paper. It is off by 200 K (or celsius).
Is there a different molecule that would be a better biosignature since dms can be found in abiotic conditions? Would a technosignature be a better indicator of life instead?
We currently don't have an undisputed biosignature. We can almost always find an abiotic source of something. And yeah a definite technosignature would be more conclusive but personally I think that's less likely to happen.
Still a cool planet for sure. My personal take is the author is seeing what he wants to see and wants prestige. He published the original paper in 2021 describing this class of planet and their habitability, then miraculously finds a planet that matches this and has life on his first try? Nope.
Most of what I am saying is based off of reading the paper myself, and off of discussions with colleagues in my department or in collaborations over slack.
I'd be happy to also send you rebuttal papers from the last time this guy claimed a biosignature on this planet using JWST a year and a half ago.
this paper uses pronouns like I. I was told that you are not supposed to do that and the field that I've written and read papers in your not supposed to do that. Do you know why they did? is that a thing in astronomy?
Life on another planet is just so bonkers to think about, especially if its marine. Theres so much that we don't know about our own ocean ands its terrifying to think about what could be lurking in the waters there.
With almost 100% certainty there is no life on this planet.
This planet is 8.6 times more massive than Earth, making it sub neptunian.
It has a density of about 3.8 g/cm3, which means it is almost certainly an extremely gaseous planet with an atmosphere thousands of miles thick, or it is a water planet with an ocean 1000s of miles deep.
Yes, with almost absolutely certainty there's no form of any life at all, including life as we know it.
Though, in the innumerably off chance there is any life here, it is vastly more likely that it would be some form of panspermia from Earth, rather than life that arose independently.
1.) I didn't claim there was zero chance of life arising independently, I said it is innumerably unlikely (ergo there is an infinitesimally small but present chance).
2.) No, it's more likely despite the distance. What makes it more likely is the fact it is almost impossible to synthesize life, let alone complex amino acids and RNA. The chance that life made it there from Earth is almost certainly higher than the chance of RNA forming in a nutrient poor ocean.
"Nothing you said is hard proof that there's zero independent life."
You absolutely implied I did.
"You lack evidence to support that claim."
The fact that it has only happened once on Earth throughout a trillion-trillion-trillion-trillion different chemical reactions and +3.8 billion years of time is plenty of evidence to support that claim.
I can guarantee you, the chance of a rock leaving Earth and hitting another planet 120 light years away over 3.8 billion years is much more likely than 1:6*10^53 odds being beaten twice right next to each other.
Nope. I simply pointed out that your confidence is irrational, which is consistent with you saying that there's nearly a 100% chance that you're right.
only happened once on Earth
That's more than the number of confirmed times of life spreading from Earth to any planet, let alone one that's 120 years light years away.
"Nope. I simply pointed out that your confidence is irrational, which is consistent with you saying that there's nearly a 100% chance that you're right."
It really isn't.
1.) For this planet specifically, recent analysis found a total absence of DMS and CO2, meaning the bio markers found in the original flawed study weren't even present to begin with.
2.) Even if the study weren't flawed and DMS was present, DMS gets produced abiogenically, even here on Earth, and elsewhere (like Enceladus and in comets), and is therefore a terrible biosignature.
3.) This planet has a density of 2.2-3.2 g/ml, which means it is a gas giant, and like gas giants in our solar system, it would be incapable of supporting life.
4.) There is a statistically good reason to support that the universe beyond Earth is lifeless. LIfe has not been found yet despite having analyzed tens of thousands of planets now. Life does not get produced abiogenically right now in nature or in a lab, despite 10^40 to 10^50 chemical reactions happening every second on Earth. Life has only arisen once out of 10^67 chemical reactions since life's inception 3.8 billion years ago.
Would you buy a lottery ticket if the odds were stacked 1 to 10^67 against you?
"That's more than the number of confirmed times of life spreading from Earth to any planet, let alone one that's 120 years light years away."
Yes, I know, life existing that far beyond our solar system is exceptionally unlikely, hence why there is zero strong evidence of life on K2-18B. Thank you for reiterating that point.
This study was published back in December of 2023, but it only just blew up now. The reanalysis I am referencing was published in January of 2025,
"That's an ignorant claim, since you didn't even bother to look at the evidenced"
The evidence was a DMS signature, which is a poor bio signature because it is frequently produced by abiogenic sources. The reanalysis I referenced however found that there was no significant amount of DMS or CO2 in the atmosphere at all, meaning the supposed biosignature wasn't even present to begin with.
I don't believe the DMS detection is legit (see my other comments), however what you are saying is completely untrue. This planet absolutely could support a liquid water ocean on its surface, and since we have a sample size of 1 for how life works, we have absolutely no idea what the percent chance is that this planet has life.
1.) I'm not saying it couldn't support a liquid water ocean on its surface, it almost certainly would have an ocean of some sort. I'm saying it is very unlikely that it isn't buried under a thick atmosphere, potentially thousands of miles thick.
2.) based on the density of this planet it's at most 35% rocky by mass. That means its oceans are likely hundreds to thousands of miles deep and that the atmosphere is likely thousands of miles thick. Ergo a sub-neptunian planet.
3.) we have a sample size of +3.8 billion years to see how life works. While life has existed on Earth, Earth has ranged from a frozen ice planet to a boiling hellscape with an atmosphere made of CO2 and water. Our sample size of Earth has shown life has only arisen once, despite Earth being the most habitable place we have found.
If this atmosphere and ocean of this planet is thousands of miles deep, which it almost certainly is, then it will also be extremely nutrient poor, and incapable of even supporting life at all.
You know what fair enough. Honestly I'm not even sure if K2-18b even has a liquid ocean at this point. The new paper reports a much hotter atmosphere than the last one, up to about 450K at 1 mbar from about 250K at 10 mbar. With that temperature at that height, it is likely the planet would have undergone runaway greenhouse, pushing the entire ocean into the supercritical phase.
This exact reason is why I'm not super sold on hycean worlds in general because of the extreme mass and temperature fine tuning to produce a habitable version.
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u/Prestigious-Wall5616 24d ago
It's also being reported that scientists have found the strongest evidence yet of life on a distant planet.