Alien life-forms could glow in spectacular reds, blues and greens to shield themselves from stellar bursts of ultraviolet (UV) radiation. And that glowing light could be how we find them, according to a new study.
Most of the potentially habitable exoplanets we know of orbit red dwarfs — the most common type of star in our galaxy and the smallest, coolest stars in the universe. And thus red dwarfs, such as Proxima Centauri or TRAPPIST-1, are at the forefront of the search for life. But if extraterrestrial life does exist on these planets, they have a major problem.
Red dwarfs often flare, or give off a burst of UV radiation that could harm life on planets around it. “A lot of the potentially habitable nearby planets we are starting to find are likely to be high-UV worlds,” said lead author Jack O’Malley-James, a research associate at the Cornell Center for Astrophysics and Planetary Science. So “we were trying to think of ways that life could deal with the high levels of UV radiation that we expect on planets orbiting red dwarf stars.”
Organisms on our own planet protect themselves from UV radiation in a variety of ways: living underground, living underwater or using sun-shielding pigments, O’Malley-James said. But there’s one way that life on Earth deals with UV that would also make life “easier” to detect — biofluorescence.