Reporting on whether James Webb Space Telescope May Have Just Detected Alien Life at Exoplanet K2-18b. Either we found a new chemical process we've never run across before, or we found alien life.
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00:00It's always been murmured in slightly hushed tones in the scientific community that the
00:05wildly successful James Webb Space Telescope has within its capability, just barely so,
00:12the possibility to characterize exoplanet atmospheres to the level of potentially picking
00:16up a biosignature.
00:18Now burning down the media, we have a story of an increasingly solid case that JWST may
00:24have actually found one, and this detection, if validated, changes everything in regards
00:30to the question of alien life in the universe.
00:33I do not say that lightly, this may well be our first detection of alien life.
00:39This is in regards to the exoplanet K2 18b, which is a sub-Neptune world about 2.6 times
00:45the radius of earth and about 8.6 times as massive and about 124 light years distant.
00:53It's well distant enough to have never interacted with earth life, thus this would not be contamination,
00:59but a true, separate abiogenesis.
01:02This planet orbits within its star's habitable zone, and the planet receives a comparable
01:07amount to earth of solar radiation from its star.
01:11More on that in a bit, because that star is a red dwarf.
01:15The planet is on a 33 day orbit, and interestingly was another discovery of the Kepler space telescope,
01:21just like another candidate for alien life, Tabby's star.
01:25The age of the star system is about 2.4 billion years.
01:29It's worth noting that oxygen has not been detected at this exoplanet, which means that
01:34there may not be photosynthesis there.
01:37When earth was 2.4 billion, there was already photosynthesis occurring.
01:42What that means will be a matter of debate as this progresses.
01:46This exoplanet became very interesting in 2019 when water vapor was detected in its atmosphere.
01:52That could indicate that it is an oceanic world.
01:56Researchers using JWST found in 2023 that the planet also has carbon dioxide and methane
02:03in the atmosphere.
02:04Both are gases linked to life, but not solely made by life.
02:08Not by a long shot for carbon dioxide.
02:11There have been several different interpretations of the data as to the question of what this
02:16world is really like, whether it's a gas planet, like Uranus or Neptune, just smaller,
02:21or if it's an ocean planet of some sort.
02:24If a water world, this planet is a candidate for what is called a Heischen world, a hypothesized
02:30class of planet where you have a liquid water ocean existing in a hydrogen rich atmosphere.
02:36Hydrogen.
02:37Ocean.
02:38Heischen.
02:39Heischen worlds would be water worlds, with likely little or no land, and thus any life
02:45on one would be aquatic in nature.
02:48There are a number of candidates for this type of world discovered by Kepler, but K2-18b
02:53has rocketed to the top of that list.
02:56In 2023, JWST made a detection of a very interesting gas in the atmosphere of this world, dimethylsulfide,
03:04which as far as anyone knows, is only produced by life.
03:08There is a link in the description below to an Event Horizon interview I did with Dr. Niku
03:12Madhusudan on that detection.
03:16The problem is that the detection was very weak, leading to much skepticism in the scientific
03:20community as to whether this detection was actually real or just noise.
03:25The researchers at the University of Cambridge, involved, were able to get more time on JWSTs
03:31to use a different instrument to redo the measurement and if it's valid, it's staggering.
03:36The detection is now at the three sigma level, that's huge because it means that there is
03:41only a 0.3% chance that this is a random fluke detection.
03:46The detection could be one of two gases, or a combination of them both, and both are thought
03:51to be unique to biology, dimethylsulfide and dimethyl disulfide.
03:56Only further work will constrain which one it is, or if it's both.
04:01What the scientific community is going to want for this discovery, however, is a five
04:05sigma detection, because extraordinary claims require extraordinary proof.
04:10Which a five sigma detection would bring the chances of it being a fluke down to a .00006
04:17chance.
04:19That level would make this a robust detection.
04:22The team believes that they can do that, with further time on JWST, which with a three
04:28sigma detection seems very likely to happen.
04:30It's worth noting that the measurement from 2023 was done with JWST's nearest and near-spec
04:37instruments.
04:38Whereas the new detection was by the MIRI instrument, which qualifies as an independent detection.
04:44The chances are good that the observations are in fact indicating what could be a biosignature
04:49on the sexoplanet.
04:51But there is still some weirdness and reason for caution.
04:54This is not a confirmed detection of alien life, and if the observations continue to hold
04:59up, the first question scientists will ask is if the chemists can think of a way where
05:04these gases could be produced in huge concentrations without biology.
05:08Maybe this is some unknown chemical process we weren't aware of going on here.
05:14One potentially weird aspect is that this planet has on the order of 20 times higher concentrations
05:19of these gases than Earth has.
05:22Interestingly, other theoretical work indicated that Heishin worlds with life would actually
05:27have these high concentrations of these two gases.
05:30It was expected.
05:32Everything so far is consistent with a Heishin world with microbial life.
05:37I want to stress caution as always, but this is the best candidate we've ever seen for
05:42a detection of a biosphere outside of Earth.
05:45If the observations hold up, then this will be difficult to knock down.
05:49It's worth noting here that these two chemicals are linked to microbial life on Earth primarily,
05:54specifically marine phytoplankton.
05:57If this is indeed an inhabited ocean world, then an analog of that seems possible.
06:03Phytoplankton are ultimately a kind of plant, which means that further observations in infrared
06:09with much larger telescopes might allow for the detection of a vegetative red edge where
06:14plant cells on Earth become highly reflective.
06:17This probably is not possible with JWST, it's simply watching the exoplanet transit its star,
06:24with the light passing through the atmosphere, and coloring it with its constituent spectra.
06:29But in the future it may be possible to directly image the planet and look for the red edge.
06:35But there are also problems.
06:36One problem is that some thinking in astrobiology is that worlds larger than two earth masses
06:41are not good candidates for life, because at some stage gravity starts getting crushing.
06:47This may not be a problem for some microbial life, extremophiles of some sort, but it does
06:52get to be a problem for anything more complex.
06:55And that high gravity would make for some very calm oceans, at least on the surface, though
07:00it's possible that there is tidal action as the planet interacts with other members
07:04of the system.
07:06This would be a very alien world indeed.
07:08If you were able to stand on it, you would feel the titanic gravity.
07:11But if you could smell these gases, the world would smell something like cooking cabbage.
07:18And oddly the analog of life there might actually taste good, as dimethyl sulfide is a food additive
07:24with a savory flavor.
07:25You taste it in things like asparagus.
07:28But you wouldn't last long in concentrations this high, because while dimethyl sulfide
07:32is normal and present in the human body, it causes medical issues, including severe bloodborne
07:38halitosis at high levels and other medical issues.
07:42And whatever is producing these gases is a massive process, because dimethyl sulfide is
07:47short lived in atmospheres.
07:50Because whatever is doing it is replenishing it actively and on a truly huge scale.
07:56That also ticks a box for life.
07:59It can do that in principle.
08:01Some other chemical process that we aren't aware of and haven't ever come across, less
08:05so.
08:06But now to the implications of this.
08:08The planet, as I mentioned, orbits a red dwarf.
08:11This would be huge news if indeed this is a biosphere detection.
08:16Because the question of red dwarf's inhabitability has been raging back and forth for years.
08:22The argument against it is that red dwarfs, when they are young, are flare stars, meaning
08:27that they would seemingly strip off the atmospheres of their habitable zone planets early on.
08:32Because the habitable zone is so close in to the star.
08:36So far, the JWST work with the TRAPPIST-1 system has borne this out.
08:41The two innermost planets appear to have no atmospheres.
08:44K2-18b does.
08:47Other work suggested that the stellar physics of red dwarfs is such that they do not flare
08:51through equators, meaning that the flares never hit their planets, which makes them
08:55completely viable for life.
08:58If this detection is valid and life remains the simplest explanation, then that changes the
09:03landscape and answers the question.
09:06The most numerous type of star by far, 73% for the Milky Way, in the universe is indeed
09:12habitable, and 80% of them are believed to have habitable zone exoplanets.
09:18And that we saw life just 124 light years away, coupled with red dwarf habitability, would strongly
09:25imply that the entire universe teems with microbial life at least.
09:30This detection probably does not hold the potential for intelligent alien life.
09:35If it holds up, then life on earth is not alone.
09:38But then comes the sad part, if all this holds.
09:41High gravity planets like this are probably not good candidates for civilizations, and that's
09:45a good thing on two counts.
09:47The first is that they would be stuck.
09:49It's unlikely that chemical rockets or any easy means could launch from this world.
09:54They very likely would have no way to perform space travel.
09:58Which means no satellites, and so on, which would greatly hamper their development.
10:03If they could develop at all in that kind of gravity.
10:06But there is a bigger problem.
10:07Heishen worlds like K2-18b might be, are thought to be exclusively oceanic worlds.
10:16If this holds for lower gravity planets, then any complex life there would be locked in a
10:20very deep ocean.
10:22And most, not all, ocean life on earth exists near the surface.
10:28Any intelligence there would be locked in their ocean with no method of smelting metal.
10:34If the majority of inhabited planets in the universe are large Heishen worlds, then there
10:39is the solution to the Fermi paradox.
10:42Intelligent life that can leave its planet is simply very, very rare.
10:46That's a sad universe to envision indeed, because if we ever spread out into the stars and start
10:51colonizing exoplanets, then we will probably be doing a lot of rescue work when we come
10:56across locked in intelligences.
10:59We will be the uplifters that rescue the Milky Way's intelligences, providing we can
11:03figure out a way to get them off their planet.
11:06Another odd effect of this would be that if this planet is fully oceanic, then that suggests
11:11that abiogenesis can indeed happen at oceanic hydrothermal vents.
11:17Yet research on earth was starting to point to hot springs in a volcanic environment on land.
11:23That might mean that abiogenesis actually has two ways to happen, again bolstering the
11:27case that microbial life is everywhere.
11:30And with a separate abiogenesis detection, it implies that abiogenesis is not complicated
11:36however it happens.
11:38So there you have it, this may, just may be it, and we are very close to the ability to
11:44confirm the first detection of alien life.
11:47If it gets shot down, we still learn something new about how these gases can form, and how
11:52it is they can end up in the atmosphere of exoplanets like this.
11:56If this is proven, it's likely this will result in Nobel Prizes and reinforce the glory of
12:02the James Webb Space Telescope.
12:04But I leave you with this, if K-1218b turns out to not be a Haitian terrestrial type world,
12:11and indeed is a sub-Neptune gas planet, the detection of these gases gets very strange indeed,
12:18because that constrains the possible non-biological chemistry option.
12:23It removes the geology from the equation, in which case,