K2-18 b and dimethyl sulfide

[Jayhawker Soule]

See Webb Discovers Methane, Carbon Dioxide in Atmosphere of K2-18 b

The article observes ...

The suggestion that the sub-Neptune K2-18 b could be a Hycean exoplanet is intriguing, as some astronomers believe that these worlds are promising environments to search for evidence for life on exoplanets.​

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"Our findings underscore the importance of considering diverse habitable environments in the search for life elsewhere," explained Nikku Madhusudhan, an astronomer at the University of Cambridge and lead author of the paper announcing these results. "Traditionally, the search for life on exoplanets has focused primarily on smaller rocky planets, but the larger Hycean worlds are significantly more conducive to atmospheric observations."​

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The abundance of methane and carbon dioxide, and shortage of ammonia, support the hypothesis that there may be a water ocean underneath a hydrogen-rich atmosphere in K2-18 b. These initial Webb observations also provided a possible detection of a molecule called dimethyl sulfide (DMS). On Earth, this is only produced by life. The bulk of the DMS in Earth’s atmosphere is emitted from phytoplankton in marine environments.​

Fun!

 

[ChristineM]

I just read about that on BBC news and was going to post something, no need now but here's the link​

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Tantalising sign of possible life on faraway world​

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Exciting times and fingers crossed.​

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[Viker]

It'd be great if there was at least microbial life there. And what @ChristineM said.

 

[sayak83]

See Webb Discovers Methane, Carbon Dioxide in Atmosphere of K2-18 b

The article observes ...

The suggestion that the sub-Neptune K2-18 b could be a Hycean exoplanet is intriguing, as some astronomers believe that these worlds are promising environments to search for evidence for life on exoplanets.​

​

"Our findings underscore the importance of considering diverse habitable environments in the search for life elsewhere," explained Nikku Madhusudhan, an astronomer at the University of Cambridge and lead author of the paper announcing these results. "Traditionally, the search for life on exoplanets has focused primarily on smaller rocky planets, but the larger Hycean worlds are significantly more conducive to atmospheric observations."​

​

The abundance of methane and carbon dioxide, and shortage of ammonia, support the hypothesis that there may be a water ocean underneath a hydrogen-rich atmosphere in K2-18 b. These initial Webb observations also provided a possible detection of a molecule called dimethyl sulfide (DMS). On Earth, this is only produced by life. The bulk of the DMS in Earth’s atmosphere is emitted from phytoplankton in marine environments.​

Fun!

I am waiting for the next pass when hopefully stronger chromatographic signals could be detected. Right now the dimethyl sulphide signature is weak.

 

[Jayhawker Soule]

I am waiting for the next pass when hopefully stronger chromatographic signals could be detected. Right now the dimethyl sulphide signature is weak.

Yep.

 

[Revoltingest]

Exciting times and fingers crossed.​

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I wonder if some exospecies is keeping its flippers or tentacles crossed?

 

[ChristineM]

I wonder if some exospecies is keeping its flippers or tentacles crossed?

Possible i suppose

 

[Mock Turtle]

It's a veeeeeeeeeeeeeeeeeeeeeery loooooooooooooooooong waaaaaaaaaaaaaaaaaaaaay away!

 

[Twilight Hue]

I wonder if some exospecies is keeping its flippers or tentacles crossed?

I'll scream if SpongeBob SquarePants is real.

 

[Revoltingest]

I'll scream if SpongeBob SquarePants is real.

 

[Jayhawker Soule]

It's a veeeeeeeeeeeeeeeeeeeeeery loooooooooooooooooong waaaaaaaaaaaaaaaaaaaaay away!

So? I doubt that anyone was hoping to sample the cuisine.

 

[Jayhawker Soule]

What a bummer ...

What is a presumed sign of life doing on a dead comet?
Touted as a "biosignature" on an alien planet,
dimethyl sulfide also seems to arise in banal ways​

On the other hand, kudos to Nora Hänni:

Scientists have discovered dimethyl sulfide (DMS), a molecule thought to have only living sources, on a cold, lifeless comet. The finding calls into question the molecule’s usefulness as a biosignature and the significance of an earlier hint of it in the atmosphere of an alien planet.​

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“This is the first sign of an abiotic source,” says Nora Hänni, a chemist at the University of Bern who presented the discovery last week at the General Assembly of the European Geosciences Union.​

Further down, the article notes:

Last year, a team of astronomers drew headlines when it claimed a possible detection of DMS in the atmosphere of K2-18b, an exoplanet 8.6 times as massive as Earth orbiting within the habitable zone of its star. Based on the cocktail of other gases detected in its atmosphere, the team believed K2-18b might have a surface ocean and that the DMS, if confirmed, would be a sign of marine life. The paper sparked breathless headlines, despite the thin evidence for the DMS. “In the media, everybody was like, ‘Oh, maybe we have detected life!’” Hänni says.​

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Hänni wasn’t so sure. She studies the surprisingly complex organic molecules found in comets, including nucleobases, the building blocks of DNA. After hearing about the K2-18b claim, Hänni wondered whether she could also find the molecule on an unquestionably lifeless body, the comet 67P/Churyumov-Gerasimenko, which the European Space Agency’s Rosetta spacecraft chased for 2 years, directly sampling the cloud of dust and gas shed from the icy space rock.​

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Just 1 day of data from Rosetta’s mass spectrometer, an instrument that can identify molecules by their specific weights, was enough for Hänni and her colleagues to find DMS.​

It may be a bummer, but it's also a great example of good science. Again, kudos to Hänni.

 

[Jayhawker Soule]

Wait; there's more! See: Gaiasignatures: A New Way to [eventually] Search for Extraterrestrial Life