Astronomers have detected a great many planets within our galaxy, the Milky Way, but as of yet none outside of them—that's unsurprising, given that the nearest galaxy to ours is many hundreds of trillions of miles away and the technology for detecting planets is still in its infancy.

Yet all of that may be about to change:

Scientists may have detected signs of a planet transiting a star outside of the Milky Way, in what could be the first planet ever to be discovered outside our galaxy.

The possible exoplanet was discovered in the Whirlpool Galaxy -- the spiral galaxy Messier 51 (M51) -- by NASA's Chandra X-ray Observatory, NASA said in a press release on Monday.

An exoplanet is a planet outside of our solar system that normally orbits a star other than our own sun in our galaxy. Until now, all other exoplanets have been found in the Milky Way, and most of them have been found less than 3,000 light-years from Earth.

This newly discovered possible exoplanet in the Whirlpool Galaxy would be about 28 million light-years away -- thousands of times farther away than those in the Milky Way.

Very cool. Next step: Contact.