We’re used to thunder and lightning here on Earth. But what might they be like on another planet? We know other worlds in the solar system have lightning strikes, for example, high in the clouds of Jupiter or during dust storms on Mars. Now, astronomers are thinking about lightning on planets beyond the solar system–and its effects on the signs of life on those planets.
In a new research paper accepted to the journal Astronomy and Astrophysics, a team of astrobiologists investigated how lightning might change some of the biosignatures—chemical signs of life—we could look for on other worlds. Overall, the results are nuanced, just like the complex atmosphere we experience here on Earth. Lightning, it turns out, can amplify some biosignatures while masking others. This both offers clues to find extraterrestrial life and complicates our observations.
Lightning appears to us as a bright flash, usually during a big rainstorm, and it’s caused by electricity in the atmosphere discharging between clouds or to the ground. It also “influences the chemistry of planetary atmospheres, including, as we all know, on Earth,” explains co-author Edward Schwieterman, an astrobiologist at the University of California, Riverside. Lightning even may have played a role in how life got started on our planet—astrobiologists think it could have brought together some of the molecules that eventually became amino acids in our bodies.
How much lightning happens on a planet depends on a whole array of factors, including how much water is in the atmosphere and how hot (or cold) it is. And if there’s enough lightning, it might significantly change what’s going on in the atmosphere. This is particularly critical for astrobiologists planning to look for specific chemicals that indicate that there is alien biology happening on planets beyond the solar system.
“A lot of the work that people do on exoplanet atmospheric biosignatures is very…
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