Scientists have found signs of a planet transiting a star outside of the Milky Way, potentially representing what could be the first-ever planet to be detected in another galaxy.
Researchers found evidence of a planet in the Messier 51 galaxy, located some 28 million light-years away from the Milky Way, as they detected a dip in brightness in the luminous "whirlpool" system. They used NASA's Chandra X-ray Telescope to observe transits, which can sometimes occur when planets pass in front of stars and block out a portion of the light.
The transit technique has been used by astronomers for years to aid the discovery of exoplanets and exoplanet candidates — all of which have been found in the Milky Way up until now. It's a method that has produced successful results, though it also presents a few challenges, particularly for scientists wanting a second viewing to confirm their findings.
"Unfortunately to confirm that we're seeing a planet we would likely have to wait decades to see another transit," said Nia Imara, who co-authored the recently published paper, presenting data that is consistent with a model of a planet candidate. "And because of the uncertainties about how long it takes to orbit, we wouldn't know exactly when to look."
While attempts to confirm the observation may be thwarted, the study's lead author, Rosanne Di Stefano, recognized that the potential discovery may help to broaden future studies and "open up a whole new arena for finding other worlds by searching for planet candidates at X-ray wavelengths, a strategy that makes it possible to discover them in other galaxies."
Astronomers previously discovered 139 new "minor planets" in the far reaches of our solar system, just beyond Neptune's orbit in the vast expanse of the galaxy, which also plays host to a free-floating world without a host star, a "hell planet" strangely similar to Darth Vader's lava homeworld of Mustafar, and a Super-Earth that's nearly as old as the universe itself.
Adele Ankers is a freelance writer for IGN. Follow her on Twitter.
Thumbnail image credit: NASA/CXC/M. Weiss
