- UV radiation flares from red dwarfs could help uncover hidden biospheres throughout the galaxy by triggering a protective reaction from any lifeforms on exoplanets known as biofluorescence.
- This is a new way to search for life in the universe, scientists say.
An energy source that astronomers have long regarded as destructive could, in fact, help discover alien life. Powerful ultraviolet radiation flares from red dwarfs could help uncover hidden biospheres throughout the galaxy by triggering a protective reaction from any lifeforms on exoplanets known as biofluorescence.
"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, a researcher at Cornell's Carl Sagan Institute, in a press statement.
"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," said co-author Lisa Kaltenegger, associate professor of astronomy and director of the Carl Sagan Institute. "Maybe such life forms can exist on other worlds too, leaving us a telltale sign to spot them."
At least some exoplanets, planets outside the solar system, exist within the "habitability range" with their own stars. In early August 2019, scientists announced the discovery of just such a planet, which they deemed a "hot Earth." These planets exist within the same Goldilocks zone that Earth does—just far enough from their star to make it at least possible for life as humans understand it to form.
Several of these Goldilocks planets, scientists further speculate, will have M-type stars, or red dwarfs. Red dwarfs are small and dim, which makes them hard for scientists to track, but they're the most common type of star in the universe. Red dwarfs are so small, some only have 10 percent the mass of Earth's sun and emit 0.01 percent as much energy.
They also have a tendency to flare up, due to their high levels of magnetic activity. These ultraviolet flares, scientists suspect, shower planets in biofluorescence. And that biofluorescence might paint planets in beautiful colors.
"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.
There are many tempting targets, like Proxima b, which scientists have previously believed uninhabitable because of its being constantly being bombarded with radiation. But according to O'Malley-James and Kaltenegger, that radiation could just make any potential life dowsed in colors. But they'll have to wait for technology to catch up with their idea. They're predicting it will be possible to test the concept within 10 to 20 years.
"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.
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