Harsh ultraviolet radiation flares from red suns, when thought to devastate surface life on planets, may help reveal concealed biospheres. A new study by the Cornell scientists suggests that their radiation could trigger a defensive glow from life on exoplanets called biofluorescence.
Lead author Jack O’Malley-James, a researcher at Cornell’s Carl Sagan Institute said, “This is a completely novel way to search for life in the universe. Just imagine an alien world glowing softly in a powerful telescope.”
Co-author Lisa Kaltenegger, associate professor of astronomy and director of the Carl Sagan Institute said, “On Earth, there is 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.”
Astronomers, for the most part, concur that a huge portion of exoplanets – planets past our nearby solar system – reside in the habitable zone of M-type stars, the amplest sorts of stars known to the universe. M-type stars frequently flare and when those ultraviolet flares strike their planets, biofluorescence could paint these universes in beautiful colors. The next generation of Earth-or space-based telescopes can detect the gleaming exoplanets if they exist in the cosmos.
Kaltenegger said, “Such biofluorescence could expose hidden biospheres on new worlds through their temporary glow when a flare from a star hits the planet.”
The astronomers used emission characteristics of common coral fluorescent pigments from Earth to create model spectra and colors for planets orbiting active M stars to mimic the strength of the signal and whether it could be detected for life.
In 2016, astronomers found a rocky exoplanet named Proxima b – a potentially habitable world orbiting the active M star Proxima Centauri, Earth’s closes star beyond the sun – that might qualify as a target. Proxima b is also one of the most optimal far-future travel destinations.
O’Malley-James said, “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.”
Kaltenegger said, “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.”
This study was funded through the Simons Foundation- published in Monthly Notices of the Royal Astronomical Society.