Scientists may have discovered a new way to search for extraterrestrial life. In a study published yesterday in the Monthly Notices of the Royal Astronomical Society, they suggest that a protective glow called biofluorescence may be indicative of life on exoplanets. Biofluorescence is the defensive response to harsh ultraviolet radiation flares from red dwarfs
‘This is a completely novel way to search for life in the universe. Just imagine an alien world glowing softly in a powerful telescope,’ said lead author Jack O'Malley-James.
‘On Earth, there are some undersea coral that use biofluorescence to render the sun's harmful ultraviolet radiation into harmless visible wavelengths, creating a beautiful radiance. Maybe such life forms can exist on other worlds too, leaving us a telltale sign to spot them,’ said co-author Lisa Kaltenegger.
Some exoplanets are known to reside in the habitable zone of the abundant M-type stars, known as red dwarfs. They flare frequently, and when the flares reach other planets, biofluorescence results. Researchers think that the next generation of telescopes, based on Earth or in space, can detect exoplanets emitting such glows: they can search for a specific signature left by photoprotective biofluorescence, the process by which ultraviolet rays are transformed into safer wavelengths.
‘Such biofluorescence could expose hidden biospheres on new worlds through their temporary glow, when a flare from a star hits the planet,’ said Kaltenegger.
To test their theory on Earth, astronomers successfully mimicked the signal by using fluorescent pigments of common corals. Back in 2016, they also found a potentially habitable exoplanet named Proxima b.
‘These biotic kinds of exoplanets are very good targets in our search for exoplanets, and these luminescent wonders are among our best bets for finding life on exoplanets,’ O'Malley-James said.
Telescopes currently in development may be able to spot this glow in a decade or two.
‘It is a great target for the next generation of big telescopes, which can catch enough light from small planets to analyze it for signs of life, like the Extremely Large Telescope in Chile,’ Kaltenegger said.