The hunt for extraterrestrial life is on, and scientists have identified the exoplanets where it is most likely to pop up.
Researchers from the University of Cambridge and the Medical Research Council Laboratory of Molecular Biology determine the best candidates for alien life, suggesting that the host star plays a significant role in developing life in a rocky planet such as Earth.
Potentially Life-Supporting Exoplanets
The study, published in the journal Science Advances, pinpoints the exoplanets that feature similar chemical conditions as Earth and consequently are best equipped to support recognizable life.
"This work allows us to narrow down the best places to search for life," first author Dr. Paul Rimmer, a postdoctoral researcher, explains in a press release from the University of Cambridge. "It brings us just a little bit closer to addressing the question of whether we are alone in the universe."
The team suggests that the rocky planets that they identified as potentially life-supporting had host stars that give off UV light, allowing specific chemical reactions to take place. These planets are also located in the habitable zone of the star, which means liquid water is possible on the surface.
Recreating The Recipe For Life
A previous study led by the recent research co-author Professor John Sutherland highlighted the potential role of cyanide in creating life on Earth.
According to the hypothesis, hydrogen cyanide was created in the atmosphere when carbon from meteorites collided with nitrogen in the young Earth. The cyanide then rained down on the planet's surface and mixed with various elements. Powered by the sun's UV light, it blossomed into the building blocks of RNA, which is believed to be "the first molecule of life to carry information."
The new study focused on the UV light in this recipe, conducting laboratory experiments that tested how quickly the components of life are formed from hydrogen cyanide and hydrogen sulphite ions in water when exposed to UV light and without it.
Senior author Didier Queloz, who is a professor from the Cavendish Laboratory, explains that chemistry in the dark is slower than chemistry in the light, so the team wanted to find out how much light is necessary for light chemistry to take place.
By comparing the experiment results of light chemistry to the UV light of various stars, the researchers were able to identify the stars that could produce enough light for planets to activate the same chemistry process that took place on Earth.
The planets that both get enough light and can feature liquid water inhibit what scientists are now calling the abiogenesis zone.
Several planets have already been identified by the Kepler telescope, but more advanced telescopes like NASA's newly launched TESS are expected to discover many more.