Traditionally, researchers have sought potential biosignatures as ways of identifying inhabited worlds: byproducts from life as we know it such as oxygen or methane that over time accumulate in the atmosphere to detectable amounts. But with current technology, according to Vladimir Airapetian, lead author of a Nature Scientific Reports study published on Nov. 2, 2017, identifying these gases on distant terrestrial exoplanets is time-consuming, requiring days of observation time. The new study suggests hunting for cruder signatures of potentially habitable worlds instead, which would be easier to detect with current resources in less time.
“We’re in search of molecules formed from fundamental prerequisites to life — specifically molecular nitrogen, which is 78 percent of our atmosphere,” said Airapetian, who is a solar scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and at American University in Washington, D.C. “These are basic molecules that are biologically friendly and have strong infrared emitting power, increasing our chance of detecting them.”
Present life on Earth tells Airapetian and his team of researchers they should look for atmospheres rich with water vapor and nitrogen, and oxygen, the product of life. Oxygen and nitrogen free-float stably in their molecular form — that is, two atoms of either oxygen or nitrogen bound together in one molecule. But in the vicinity of an active dwarf star, extreme space weather sparks distinct chemical reactions, which researchers can use as indicators of atmospheric composition.
Source & further reading:https://www.nasa.gov/feature/goddard/2017/atmospheric-beacons-guide-nasa-scientists-in-search-for-life
Journal article:https://www.nature.com/articles/s41598-017-14192-4
Credits: NASA’s Goddard Space Flight Center/Mary Pat Hrybyk
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