(ORDO NEWS) — Photosynthesis is probably the most important chemical reaction for life on Earth. This is the process that plants use to convert sunlight into energy.
Thanks to photosynthesis, the Earth’s atmosphere is 20% oxygen. No photosynthesis means no life on Earth as we know it.
Of course, photosynthesis has evolved to match the bright yellow star that emits most of its light in the visible spectrum. But sun-like stars make up less than 8% of the main sequence stars in our galaxy.
Red dwarfs, on the other hand, make up 75% of main sequence stars. According to statistics, the vast majority of potentially habitable planets revolve around red dwarfs.
And red dwarfs are much smaller and colder than the Sun. Most of the light they emit is in the infrared.
But does it have the effect that is needed to activate photosynthesis? In a recent study, a group of scientists tried to find out.
To do this, they created a starlight simulator. This is an array of LEDs tuned to mimic the spectrum of a red dwarf.
They then recreated an atmosphere that could have been typical of an early habitable world, added some bacteria, and lit them up with simulated starlight.
They started with cyanobacteria, which were among the first organisms on Earth to use photosynthesis to produce oxygen. They survive well in harsh environments.
The cyanobacteria grew well in the red dwarf’s infrared light, so the team repeated the experiment with red and green algae. They flourished too.
Thus, even though red dwarfs do not emit the type of light that led to the evolution of photosynthesis on Earth, terrestrial organisms could live in such conditions.
This is great news for those who want to find extraterrestrial life.
Of course, red dwarfs have other problems that could rule out the existence of life on their planets, but this remarkable study has shed some light on our understanding of life on other planets.
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