Scientists believe they've spotted the first planet outside the Milky Way

NASA says a group of scientists may have discovered signs of a new planet beyond the Milky Way. The potential discovery could be the first-ever planet found in another galaxy. 

The potential planet, which is unnamed and roughly the size of Saturn, was spotted in the spiral galaxy Messier 51, or what's known as the Whirlpool Galaxy, about 28 million lightyears away from the Earth, according to NASA. 

Researchers made the discovery with a NASA telescope, called the Chandra X-ray Observatory, and by using a new technique to search for planets known as the X-ray transit method. Exoplanets, which NASA defines as planets outside of our solar system, are difficult for astronomers to detect.