Water May Not Be the Only Sign of Alien Life

By Charles Q. Choi, ISNS Contributor | June 23, 2018 08:45am ET

(Inside Science) – When it comes to looking for alien life, scientists mostly focus on where there is water. Now researchers suggest that looking at "bioessential" elements such as phosphorus and molybdenum could help judge a world's potential for life.

There is life virtually wherever there is water on Earth, from clouds high above the surface to the deepest layer of Earth's crust. As such, the search for life outside Earth typically concentrates on worlds that are "habitable," possessing temperatures conducive to hosting liquid water on its surface.

For example, although the surface of Venus is currently hot enough to melt lead, a 2016 study suggested it may have been habitable until as recently as 715 million years ago. Scientists have even conjectured that if life once existed on Venus, it still might survive within its clouds.

However, "there are of course other ingredients needed for life as we know it," said study senior author Avi Loeb, chair of astronomy at Harvard University in Cambridge. For example, on Earth, elements that are key to how much life oceans hold may include nitrogen and phosphorus. Nitrogen is needed to create proteins, and both nitrogen and phosphorus are key ingredients of DNA and RNA. Several recent studies suggest the increased availability of phosphorus in the oceans about 635 million to 800 million years ago may have even helped support the evolution of animals on Earth, the researchers noted.

More:
https://www.livescience.com/62901-signs-of-alien-life.html