Stellar storms may light up signs of life on alien planets

Stellar storms, or eruptions of material that are regularly spewed into space by stars, could help scientists search for potentially habitable environments on alien planets, according to a new study. Most stars, including the sun, produce explosions on their surfaces that spit powerful particles out into space. These expulsions can rain down on nearby planets, and the new study shows that these interactions could create chemical “beacons” in the planetary atmospheres that reveal the presence of potentially life-friendly environments. “We’re in search of molecules formed from fundamental prerequisites of life — specifically molecular nitrogen, which is 78 percent of our atmosphere,” Vladimir Airapetian, a solar scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said in a statement from the agency. Airapetian is lead author on the new paper, which argues that modern instruments could detect these prerequisite chemicals faster than they could detect signs of existing life-forms. “These are the basic molecules that are biologically friendly and have a strong infrared emitting power, increasing our chance of detecting them,” Airapetian said. Because Earth is the only known habitable world so far, scientists use it as a guide for what to expect when hunting for life beyond the solar system. Water vapor, nitrogen and oxygen are all products of life as we know it. While the sun releases a relatively light stream of charged particles and occasional, energetic bursts, other stars can release far larger, more energetic and more frequent doses that bathe their nearby planets. If the charged particles interact with the atmosphere of a planet containing those products of life — water vapor and molecular nitrogen and oxygen — the interaction could trigger a cascade of chemical reactions that form what Airapetian and his colleagues call “atmospheric beacons” — molecular oxygen, nitric oxide and hydroxyl (one atom each of oxygen and hydrogen, bound together), according to the statement. Then, if the conditions are right, researchers could detect those beacons. As light from the star hits the planet’s atmosphere, it would cause the beacons to send energy into space as infrared radiation. Examining the radiation from the atmosphere of such a world would reveal the presence of these beacons. Since it takes a significant amount of molecular oxygen and nitrogen to create the beacons, their detection could indicate an atmosphere filled with biologically friendly chemistry, indicating a potentially habitable exoplanet. “Taking what we know about infrared radiation emitted by Earth’s atmosphere, the idea is to look at exoplanets and see what sort of signals we can detect,” said study co-author Martin Mlynczak. “If we find exoplanet signals in nearly the same proportion as Earth’s, we could say that a planet is a good candidate for hosting life.”

Fascinating!!    🙂

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