The first signs of a potential new planet outside the Milky Way have been spotted by NASA in the Chandra X-ray Observatory.
A study published yesterday in Nature Astronomy by US astronomers reported 'bold' evidence of a new planet that would be the first planet seen to orbit a star outside our galaxy.
The sighting was located in Messier 51 (M51), also called the Whirlpool Galaxy.
Astronomers have already found all exoplanets in the Milky Way, in other words, planets outside our solar system but in the same galaxy. Thus, a planet outside the Milky Way is a discovery of a much greater scale.
NASA says an exoplanet in M51 would be about 28 million lightyears away.
That means it would be thousands of times farther away than exoplanets in the Milky Way.
"We are trying to 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," said Rosanne Di Stefano, who led the study at the Center for Astrophysics at Harvard & Smithsonian.
However, more data is needed to officially classify it as a planet outside the galaxy.
Nia Imara, a co-author from University of California at Santa Cruz said: "Unfortunately to confirm that we’re seeing a planet we would likely have to wait decades to see another transit.
"And because of the uncertainties about how long it takes to orbit, we wouldn't know exactly when to look."
