Fluorescent glows on other planets may reveal alien life

New technique promises to help scientists in the search for extraterrestrial life: observing the ultraviolet radiation emanating from red stars
When it comes to detecting life on other planets, there are many possible techniques and approaches. And now it looks like we have one more: analyzing the ultraviolet radiation coming from red stars.

But how would that work? Well, here on Earth this band of radiation is absorbed by some biofluorescent species, such as many plants and various species of biofluorescent fish and corals. And that glow can be captured by special filters.
So if on other planets there is also some kind of similar life, we could see the same way!

Of course, because of the distance, things wouldn’t be that easy, but scientists are excited about the new approach.
“This is a completely new way of looking for life in the universe; imagine an alien world glowing softly in a powerful telescope,” said Jack O’Malley-James, a researcher at the Carl Sagan Institute and lead author of the research published in the Monthly Notices of the Royal Astronomical Society.

Bioluminescence in plankton recorded in Puerto Rico. Credits: Colourbox / P. Grebenkin / disclosure
It is worth remembering that bioluminescence is one thing and biofluorescence is quite another:

Bioluminescence is the property of beings capable of emitting light by themselves, such as fireflies, for example, which capture harmful ultraviolet and emanate light visible to the naked eye;
Biofluorescence is the ability to absorb ultraviolet radiation from the Sun, transforming it into harmless wavelengths, generating a coloration invisible to the naked eye.
“Perhaps these life forms could also exist on other worlds,” said study co-author Lisa Kaltenegger, professor of astronomy and director of the Carl Sagan Institute.

The technique is based on the detection of biofluorescent organisms found on the seafloor by biologist David Gruber. He was able to record the glow of at least 180 species using underwater cameras with a yellow filter, which blocks blue light and reveals fluorescence.

Biofluorescence in corals recorded by David Gruber using a yellow filter, which blocks blue light and reveals fluorescence. Credits: David Gruber
“This biofluorescence can reveal hidden biospheres on new worlds through their temporary glow when a glare from a star hits the planet,” Kaltenegger said.

According to her, the process called photoprotective biofluorescence makes the absorbed ultraviolet rays in longer and defined wavelengths, leaving a specific signal for which astronomers can search.

To determine the parameters of the biofluorescent signal that they might encounter on other worlds, researchers used characteristics of fluorescent pigments from common Earth corals to create models of spectra and colors that can be investigated on planets that would be able to harbor life forms.

And with a new generation of telescopes we could detect exoplanets that contain this glow, if they really exist.

“It’s a big target for the next generation of large telescopes, which can pick up enough light from small planets to analyze them for signs of life,” added Kaltenegger.