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TL;DR - K2-18b - detected dimethyl sulfide and dimethyl disulfide, false positive possibility is now very low - "produced by marine-dwelling organisms on Ear

TL;DR - K2-18b - detected dimethyl sulfide and dimethyl disulfide, false positive possibility is now very low - "produced by marine-dwelling organisms on Earth", possibility they were produced by other processes (unrelated to life as we know it) not high but maybe unknown unknowns - other factors like distance from the star are in favor of life & water - previous studies detected methane and carbon dioxide

sph 2y ago
> false positive possibility is very low No, it means we will soon discover how these compounds form naturally. Would love to be wrong, of course.
- throwaway290 2y ago
  I meant (and I think the article meant) false positive of gas detection not life
- actionfromafar 2y ago
  Maybe the are cooking a lot of paper over there. https://en.wikipedia.org/wiki/Kraft_process https://en.wikipedia.org/wiki/Kraft_process
- nottorp 2y ago
  If plankton farts them, it's natural too, right?
dvh 2y ago
Parent is a flare star
- throwaway290 2y ago
  Like the sun, I guess
psychoslave 2y ago
Is dimethil something expected to be generated with really procaryote life forms, or only from those with more complexe structures?
guax 2y ago
> The observations also provided a tentative hint of dimethyl sulfide (DMS), a possible biosignature gas, but the inference was of low statistical significance. From the source paper. It is a very important result but not definitive, false positive is still possible as well as us finding a new way in which DMS can form without a biological process. Still freaking exciting and fantastic scientific achievement. JWST is already bearing incredible fruits.
energy123 2y ago
> false positive possibility is now very low It's not that low, unfortunately. From the article: > They say their observations have reached the ‘three-sigma’ level of statistical significance. This means there's a 0.3% probability the detection occurred by chance. And to reach the accepted level that would mean scientific discovery, observations would have to meet the five-sigma threshold. In other words, there would need to be below a 0.00006% probability they occurred by chance.
- fullstackchris 2y ago
  Thats what I'd like to know, is this the kind of process that we can _get_ to 6 sigma by more observation time? Or would we need other observations / thats "as good as it gets" for the Webb's capabilities?

sph 2y ago

> false positive possibility is very low No, it means we will soon discover how these compounds form naturally. Would love to be wrong, of course.

throwaway290 2y ago
I meant (and I think the article meant) false positive of gas detection not life
actionfromafar 2y ago
Maybe the are cooking a lot of paper over there. https://en.wikipedia.org/wiki/Kraft_process https://en.wikipedia.org/wiki/Kraft_process
nottorp 2y ago
If plankton farts them, it's natural too, right?

dvh 2y ago

Parent is a flare star

throwaway290 2y ago
Like the sun, I guess

psychoslave 2y ago

Is dimethil something expected to be generated with really procaryote life forms, or only from those with more complexe structures?

guax 2y ago

> The observations also provided a tentative hint of dimethyl sulfide (DMS), a possible biosignature gas, but the inference was of low statistical significance. From the source paper. It is a very important result but not definitive, false positive is still possible as well as us finding a new way in which DMS can form without a biological process. Still freaking exciting and fantastic scientific achievement. JWST is already bearing incredible fruits.

energy123 2y ago

> false positive possibility is now very low It's not that low, unfortunately. From the article: > They say their observations have reached the ‘three-sigma’ level of statistical significance. This means there's a 0.3% probability the detection occurred by chance. And to reach the accepted level that would mean scientific discovery, observations would have to meet the five-sigma threshold. In other words, there would need to be below a 0.00006% probability they occurred by chance.

fullstackchris 2y ago
Thats what I'd like to know, is this the kind of process that we can _get_ to 6 sigma by more observation time? Or would we need other observations / thats "as good as it gets" for the Webb's capabilities?