Atmospheric pollution could be the sign of advanced extraterrestrial civilization
This study is the first time pollution has been examined as a possible technosignature.
Artist’s illustration of a technologically advanced exoplanet. The colors are exaggerated to show the industrial pollution, which otherwise is not visible.
Credits: NASA/Jay Freidlander
Nitrogen dioxide is part of a group of gaseous air pollutants produced due to road traffic and other fossil fuel combustion processes. In the lower atmosphere (about 10 to 15 kilometers or around 6.2 to 9.3 miles), NO2 from human activities dominate compared to non-human sources. Therefore, observing NO2 on a habitable planet could potentially indicate the presence of industrialized civilization.
Stellar Flares as an Aid to Life Detection by Paul Gilster on December 23, 2020
The interesting transient associated with Proxima Centauri and monitored by Breakthrough Listen reminds us of a key fact about red dwarf stars and the planets around them. Such stars, especially in their youth, are prone to high flare activity, meaning violent, unpredictable emissions that can deplete atmospheric gases like ozone. Even if the atmosphere survives strong stellar winds, the loss of ozone can lead to high levels of ultraviolet radiation reaching the surface and compromising any life there.
That stellar flares can be dramatic is captured in the image below, showing a filament eruption from the Sun and accompanying solar flares (credit: NASA/GSFC/SDO). As striking as the image is, it depicts activity on an older star less prone to strong flare activity than younger, smaller stars. We’re also fortunate in having the shield offered by Earth’s magnetic field, which can deflect
Robust stellar flares might not prevent life on exoplanets, could facilitate its detection phys.org - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from phys.org Daily Mail and Mail on Sunday newspapers.
Credit: NASA s Goddard Space Flight Center/S. Wiessinger
Although violent and unpredictable, stellar flares emitted by a planet s host star do not necessarily prevent life from forming, according to a new Northwestern University study.
Emitted by stars, stellar flares are sudden flashes of magnetic imagery. On Earth, the sun s flares sometimes damage satellites and disrupt radio communications. Elsewhere in the universe, robust stellar flares also have the ability to deplete and destroy atmospheric gases, such as ozone. Without the ozone, harmful levels of ultraviolet (UV) radiation can penetrate a planet s atmosphere, thereby diminishing its chances of harboring surface life.
By combining 3D atmospheric chemistry and climate modeling with observed flare data from distant stars, a Northwestern-led team discovered that stellar flares could play an important role in the long-term evolution of a planet s atmosphere and habitability.
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Upside of volatile space weather
Although violent and unpredictable, stellar flares emitted by a planet’s host star do not necessarily prevent life from forming, according to a new Northwestern University study.
Emitted by stars, stellar flares are sudden flashes of magnetic energy. On Earth, the sun’s flares sometimes damage satellites and disrupt radio communications. Elsewhere in the universe, however, robust stellar flares also have the ability to deplete and destroy atmospheric gases, such as ozone. The destruction of gases like ozone could allow harmful levels of ultraviolet (UV) radiation to penetrate a planet’s atmosphere, thereby diminishing its chances of harboring surface life.