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Our nearest astronomical neighbor is Proxima Centauri, a tiny red dwarf star some 4.25 light-years from here. In recent years, Proxima has become the focus of huge attention. In 2016, astronomers discovered it hosted an Earth-sized exoplanet in the habitable zone where conditions should be ripe for liquid water.

Then last year, astronomers spotted an unusual radio signal that appeared to be coming from that part of sky. The most likely source of the signal is radio interference on Earth but various astronomers have discussed the possibility that it could be a technosignature from a Proxima Centauri civilization.

All this excitement masks a much more basic and obvious question, which is whether a red dwarf could host life at all, given that the light it produces is much cooler, dimmer and redder than the light that supports life on Earth.

Now we get an answer of sorts thanks to the work of Riccardo Claudi at the Astronomical Observatory of Padova in Italy and colleagues who have recreated the red dwarf light spectrum and shown that bacteria can harvest it for photosynthesis.

Their work suggests that, at least as far as the spectrum of light is concerned, red dwarfs have the capability to host photosynthetic life forms. In turn, this hints at the kind of biosignature these lifeforms might present to distant observers, such as ourselves.

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