James Webb Space Telescope

Also: Did Webb find signs of life on exoplanet K2-18 b?

NASA’s James Webb Space Telescope completed another scheduled observation of exoplanet K2-18 b on April 26, 2024. These most recent Webb observations reportedly went for eight hours. The observations follow the tentative and highly debated result from September of last year, when Webb reportedly observed a molecule called dimethyl sulfide – a possible life sign – in this exoplanet’s atmosphere. The new Webb observations now need to be analyzed. And it will likely be at least a few months before we hear more about whether Webb found the dimethyl sulfide signal again or more details about the planet itself. But know that this exoplanet is being scrutinized, and that it might become famous as the first place in our Milky Way galaxy – behind our own Earth – where we have found signs of life.

So did Webb spot signs of life on this planet, located only about 124 light-years from Earth, in the direction of the constellation Leo the Lion? On September 11, 2023, NASA announced that Webb had made some exciting discoveries while observing this distant world. They said the planet has methane and carbon dioxide in its atmosphere, which indicates it might be a Hycean world, one with a deep hydrogen atmosphere and global water ocean.

But the extraordinary news was that Webb had found hints of dimethyl sulfide (DMS). On Earth, only life produces dimethyl sulfide, such as bacteria and phytoplankton in oceans.

What will happen next? The finding of dimethyl sulfide needs to be confirmed. Then, scientists have to learn more about the exoplanet itself. While it is in the habitable zone of its star, its environment could still be unfavorable to life. As NASA said, it may have a hostile environment due to its active star, or its ocean may also be too hot to be habitable.

When I see those endless background galaxies in those images, I kind of lose my mind that each is a hundred billion stars which have existed for billions of years, and the light has taken billions of years to reach us, and there might have been life there, and hundreds of civilisations might have come and gone, and 30 pixels on an image detector is the first and possibly only time we'll know about that galaxy. And there are like 200 in that tiny closeup.

also xp they found dimethyl sulphide on one of the comet nuclei they visited, which couldn't have supported life, so it's in doubt as a marker of biological processes.

That's a Luck Dragon surely