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Other Worlds Might Pollute Atmosphere on Purpose, New Study Finds

2024-07-01T14:03-07:00

If aliens are also looking for signs of life on other planets, they could find us by observing the artificial gases in Earth's atmosphere. A paper published last week in the Astrophysical Journal suggests we use this strategy in our own search for extraterrestrials, who might release pollutants to save their world.

While dangerous greenhouse gases have raised temperatures on our planet and depleted the ozone layer, the study says that aliens may intentionally release less harmful emissions to avert a dangerous cooling event, such as an ice age. This atmospheric engineering would be a clear technosignature — an indicator of technology on a different planet.

"In contrast to passive incidental by-products of industrial processes, artificial greenhouse gases would represent an intentional effort to change the climate of a planet," the paper states. "An extraterrestrial civilization may be motivated to undertake such an effort to arrest a predicted snowball state on their home world or to terraform an otherwise uninhabitable terrestrial planet within their system."

Researchers propose using infrared technology to detect artificial gases with relatively low toxicities. Not all greenhouse gases can destroy layers of an atmosphere, and scientists agree that if aliens were terraforming sustainably, they would use less dangerous emissions than the chlorofluorocarbons or nitrogen dioxide found on Earth.