Signs of life?

HooRU

WASHINGTON, April 16 (Reuters) - In a potential landmark discovery, scientists using the James Webb Space Telescope have obtained what they call the strongest signs yet of possible life beyond our solar system, detecting in an alien planet’s atmosphere the chemical fingerprints of gases that on Earth are produced only by biological processes.

https://www.reuters.com/science/scientists-find-strongest-evidence-yet-life-an-alien-planet-2025-04-16/?utm_campaign=trueAnthem%3A+Trending+Content&utm_medium=trueAnthem&utm_source=facebook&fbclid=IwY2xjawJtU3xleHRuA2FlbQIxMQABHlgZ4QQTKb3MQBZeOnH2226n-yswiy0Xfv1Dj-XhyCTAhTbVh2yjT9fzizGD_aem_-TIcnHqlWkUsfFKvpbBVOw

real_aurgathor

Single celled microbial life can arise very quickly and easily – on Earth it took less than 400M years after its formation, and it’s strongly suspected that Mars also had life. However, transitioning from single celled life to multicellular life is much more difficult and took much more time on Earth. The last step, becoming ‘self aware’ and transitioning to intelligent life is the most complicated step, and lots of things had to go “just right” for humans.

In any case, that planet orbits a red dwarf about half as massive as the Sun, and red dwarves are also flare stars, so they are not as ‘life friendly’ as orange (0.6M - 0.9M) or yellow (0.9M - 1.1M) dwarf stars.

Looking at the star’s wiki page, notwithstanding of the recent discovery, it’s a less than ideal candidate.
https://en.wikipedia.org/wiki/K2-18b
https://en.wikipedia.org/wiki/K2-18
https://en.wikipedia.org/wiki/Habitability_of_red_dwarf_systems

Since it’s a relatively high mass planet, it should be able to hold onto it’s water and atmosphere reasonably well in spite of the flares, especially if it also has a decent magnetic field, but the environment (lots of UV and flares) is not particularly conducive for complex life forms as we know them.

real_aurgathor

There were 2 minor issues in my above post, so I decided to provide some additional explanation.

real_aurgathor especially if it also has a decent magnetic field,

Planets in red dwarves’ goldilock zone are normally tidally locked to their host star, so they won’t have much of a dynamo effect like Earth has, which is how planetary magnetic fields are normally generated.

real_aurgathor but the environment (lots of UV and flares) is not particularly conducive for complex life forms as we know them.

Water can scatter and absorb *some* UV ( see: https://homescale.net/does-water-filter-out-uv-rays/ ) so UV should have significantly less effect on underwater life. It shall be noted that while pure water does not absorb much UV, water that has impurities (essentially all surface water on Earth, and likely to be elsewhere) will absorb UV much more.

The measured absorptivities were much lower than all previously reported values in the 200–300 nm region, but gave considerably better agreement with theory and aligned well with the edge of a set of recent vacuum UV measurements on high purity water. It appears that previously reported absorptivities of liquid water in the 200–300 nm region are too large by up to two orders of magnitude, due to the presence of oxygen and of persistent absorbing impurities.

https://pubs.aip.org/aip/jcp/article-abstract/72/8/4416/216540/The-ultraviolet-absorption-spectrum-of-liquid?redirectedFrom=fulltext

Since red dwarfs are by far the most common type of star in the Milky Way at around 60 - 70%, it’s not unreasonable to hear more about planet discoveries around red dwarfs than other type of stars. However, the goldilock size for host stars is still 0.6M - 1.1M, even though the ‘possibility range’ is much-much wider, and even include ‘exotics’ such as neutron stars!!! 😲
( https://en.wikipedia.org/wiki/Habitability_of_neutron_star_systems )