Scientists have found two planets outside our solar system that could host extra-terrestrial life

NASA

An artist's illustration of the exoplanet Kepler-452b

• Scientists may have just come closer to answering questions about whether other planets in the universe may be able to support life.
• The researchers used data on the UV levels required to make the molecular structures needed within a functioning cell.
• The team used this data to search for planets receiving similar UV levels from stars nearby, and have narrowed down the possibilities to two planets outside of our solar system.

Are we alone in the universe? What prerequisites are there for supporting life on another planet? Are there any other planets out there that fit the bill?

We may now be closer to solving some of these puzzles thanks to a recent report published in "Science Advances", in which a team of researchers have highlighted the conditions required for a similar phenomenon to take place on another planet.

According to the researchers, the amount of UV light emanating from nearby stars could have been a decisive factor in the beginning of life on Earth.

"Life as we know it requires a variety of molecular structures that perform various functions within the cell," explained astrophysicist Paul Rimmer from the University of Cambridge in a guest article for The Conversation. "These include DNA, RNA, proteins and cell membranes, which are made up of relatively simple building blocks (lipids, nucleotides and amino acids). For a long time it was a mystery where those building blocks came from, but recently there have been major breakthroughs in determining how they arose on the surface of the early Earth."

The key to life on other planets

According to Rimmer, hydrogen cyanide and negatively charged ions, when combined with just the right amount of UV light, can create the building blocks necessary for the formation of life.

It was a study from 2015 , which ascertained the correct quantity of UV light required to start the process, that sparked the researchers' more recent investigations. From there, researchers were able to search for stars in space emitting this same amount of UV. The corresponding zone they found, they now call the abiogenesis zone.

Other conditions a planet must have in order to be capable of sustaining life include a rocky terrain, and to be located in the "habitable zone". This is essentially the space needed between a planet and a central star for water to be permanently available in liquid form, without evaporating or freezing.

Although the habitable and abiogenesis zones don't always overlap, the researchers discovered two planets outside of our solar system (known as an exo-planet): one, Kepler 425b, has been described as Earth's cousin and is considered one of the exoplanets on which life similar to that on Earth could be possible.

"We found two candidates," Rimmer said. "Kepler-452b is the smallest exoplanet we know that resides definitively located in both the habitable and abiogenesis zones. Exoplanet Kepler-62e may also be in the abiogenesis zone, but it is not as likely to be rocky."

By  victor ken