{"id":18663,"date":"2018-01-24T21:24:23","date_gmt":"2018-01-24T13:24:23","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/scientists-fine-tune-the-formula-for-finding-the-signature-of-life-in-alien-atmospheres\/"},"modified":"2018-01-24T21:24:23","modified_gmt":"2018-01-24T13:24:23","slug":"scientists-fine-tune-the-formula-for-finding-the-signature-of-life-in-alien-atmospheres","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/scientists-fine-tune-the-formula-for-finding-the-signature-of-life-in-alien-atmospheres\/","title":{"rendered":"Scientists fine-tune the formula for finding the signature of life in alien atmospheres"},"content":{"rendered":"
\"Alien
An artist\u2019s conception shows the light of an alien star shining through a planet\u2019s atmosphere. (NASA Goddard via YouTube)<\/figcaption><\/figure>\n

Is the presence of oxygen in the atmosphere of an alien world the only sure-fire sign that life is present? Not necessarily: Scientists say the chemical signature of biological activity is likely to be more subtle, involving a mix of gases that might seem out of whack.<\/p>\n

In a paper published today in Science Advances, researchers say future observatories such as NASA\u2019s James Webb Space Telescope should look for the signature of atmospheric gases that would be in disequilibrium if it weren\u2019t for biological processes.<\/p>\n

The study\u2019s lead author, Joshua Krissansen-Totton of the University of Washington, says looking for oxygen alone shouldn\u2019t be the sole strategy in the search for life on extrasolar planets.<\/p>\n

\u201cThis idea of looking for atmospheric oxygen<\/span> as a biosignature has been around for a long time. And it\u2019s a good strategy \u2014 it\u2019s very hard to make much oxygen<\/span> without life,\u201d he said in a news release. \u201cBut we don\u2019t want to put all our eggs in one basket. Even if life is common in the cosmos, we have no idea if it will be life that makes oxygen<\/span>. The biochemistry of oxygen<\/span> production is very complex and could be quite rare.\u201d<\/p>\n

He and his colleagues propose an alternative chemical formula to look for: methane plus carbon dioxide, minus carbon monoxide.<\/p>\n

\"Atmospheric
Future telescopes will be able to observe atmospheres of distant planets for signs of life. Modern-day Earth\u2019s oxygen\/ozone combination is a sign of life on Earth (top left). For an alien analog to the early Earth (bottom left), the combination of methane and carbon dioxide would provide an alternative biosignature. (UW Illustration \/ J. Krissansen-Totton via AAAS)<\/figcaption><\/figure>\n

\u201cWe need to look for fairly abundant methane and carbon dioxide on a world that has liquid water at its surface, and find an absence of carbon monoxide,\u201d said co-author David Catling, a UW professor of Earth and space sciences. \u201cOur study shows that this combination would be a compelling sign of life. What\u2019s exciting is that our suggestion is doable, and may lead to the historic discovery of an extraterrestrial biosphere in the not-too-distant future.\u201d<\/p>\n

The formula was derived by looking at what scientists believe is the early history of Earth\u2019s atmosphere, before oxygen came to dominate. It aims to rule out non-biological methods of producing methane. In addition, the researchers assume that carbon monoxide wouldn\u2019t build up in the atmosphere of a planet with life.<\/p>\n

\u201cCarbon monoxide is a gas that would be readily eaten by microbes,\u201d Krissansen-Totton explained. \u201cSo if carbon monoxide were abundant, that would be a clue that perhaps you\u2019re looking at a planet that doesn\u2019t have biology.\u201d<\/p>\n

It\u2019s not too early to figure out the formula to use when looking for life: The James Webb Space Telescope is scheduled for launch in 2019, and other future telescopes are also likely to be capable of analyzing the atmospheres of planets far beyond our solar system.<\/p>\n