Alien life may be hiding in purple hue of universe: Scientists

In a new research, it has been found that astronomers may need to study the pinpoints of purple to discover life on far-off planets.

The new research has discovered the light signals which travel from worlds that lack sunlight and oxygen, like in many exoplanets found so far.

The dominant colour which gives a signal of life on Earth is green because of the plants and bacteria which transform sunlight into energy with the help of green chlorophyll. 

On the planet, which orbits around smaller and dimmer stars, the organisms are expected by scientists to survive if they run their metabolism on other infrared light. 

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Infrared-powered bacteria exist in different niches on Earth, especially where there is no penetration of sunlight like deep-sea hydrothermal vents or murky marshes.

According to the study published in the journal Monthly Notices of the Royal Astronomical Society, an astrobiologist at Cornell University Ligia Fonseca Coelho and her co-authors grew various bacteria and measured the wavelengths of light which were reflected by them and simulated them with the kind of light signals seen in other worlds.

As per the study researchers, telescopes like the Extremely Large Telescope - which has been under construction in Chile - and the Habitable Worlds Observatory - which is being planned out, will be able to look for these light spectra.

In a statement, the director of Carl Sagan Institute and a Cornell University astronomer and co-author Lisa Kaltenegger said, "We need to create a database for signs of life to make sure our telescopes don't miss life if it happens not to look exactly like what we encounter around us every day."

Purple bacteria, which belong to a phylum known as Pseudomonadota, are able to thrive in low-oxygen environments, as per the scientists.

Twenty species of purple non-sulfur-producing bacteria and 20 species of purple sulfur-producing bacteria were grown by Coelho and her colleagues.

These species were gleaned by them from different environments, which included pre-existing lab colonies; a pond on Cornell's campus in upstate New York and the waters near Cape Cod, Massachusetts.

"Our models show that depending on the surface coverage of the biota and the cloud coverage, a wide variety of terrestrial planets could show signs of purple bacteria surface biopigments," stated the researchers, in their paper. 

"While it is unknown whether life — or purple bacteria — can evolve on other worlds, purple might just be the new green in the search for surface life," they added.