A new study has detailed a revolutionary way to look for extraterrestrials – and that is by searching for man-made, or alien-made, object orbiting a planet.
There are over 100,000 man-made objects orbiting the Earth, and the same would likely apply to alien civilisations who are as advanced, or more so, than us.
To spot a planet with orbiting satellites, astronomers could use the ‘transit method’ – which is where light observed from a star dips as a planet passes by it, thus how exoplanets are found.
The same could apply to planets with orbiting collective junk, which astrophysicist Hector Socas-Navarro from the Canary Islands Institute of Astrophysics in Spain has called a Clarke Exobelt (CEB).
Writing in a paper published on arXiv.org, Dr Socas-Navarro says: “The idea is to examine the region of space around a planet where potential geostationary or geosynchronous satellites would orbit hereafter, the Clarke Exobelt.
“Civilisations with a high density of devices and/or space junk in that region, but otherwise similar to ours in terms of space technology, our working definition of ‘moderately advanced’, may leave a noticeable imprint on the light curve of the parent star.”
However, one stumbling block in looking for these CEBs is that astronomers could mistake natural satellites – such as moons and rings like the ones around Saturn – could be mistaken for manufactured products.
But Dr Socas-Navarro does not see this as an issue as no one has yet to find a moon or anything of similar ilk around an exoplanet.
He told New Scientist: “The nice thing is that looking for Clarke Exobelts comes for free with the search for moons and rings.
“It’s as if someone gives you a free lottery ticket. You know it’s utterly unlikely that you’ll win the prize but wouldn’t you check, just in case?”