Earth-like #planets orbiting small, red #stars known as M-dwarfs are often considered the right size and at the right distance from their sun to harbor #life.
However, these worlds may not have the right kind of light to support multicellular organisms.
Here on Earth, #plants and #bacteria turn sunlight into energy through #photosynthesis, releasing oxygen as a byproduct.
During the Great Oxidation Event around 2.3 billion years ago, significant quantities of #oxygen began to accumulate in our #atmosphere, eventually reaching levels capable of supporting multicellular life.
According to our understanding, a similar process would have to occur on other planets for complex life to start evolving.
#Photosynthesis requires a specific kind of light from 400 to 700 nanometers that plants, #algae and #cyanobacteria need to thrive.
Although it was known that light from M-dwarf stars like TRAPPIST-1 is mostly #infrared, which falls outside this range, what was unknown was how this would slow down the evolutionary clock.
By comparing light from these red stars to our own sun and modeling the oxygen production of various #bacteria, redearchers calculated that because these stars produce so little usable energy, the accumulation of oxygen would be far too slow.
Potentially, on a #planet like TRAPPIST-1e, it would take 63 billion years in a worst-case scenario to reach the oxygen levels seen on Earth through photosynthesis.
#astronomy #astrobiology #exoplanets
https://phys.org/news/2026-01-complex-life-planets-orbiting-galaxy.html
Preprint by Soliz & Welsh (2026):
https://arxiv.org/abs/2601.02548