Astronomers say they may have detected a potential planet outside of our galaxy. The potential world, called M51-ULS-1b, orbits both a massive star and a dead star in the Whirlpool galaxy, about 28 million light-years from Earth. If the object’s existence is confirmed, then it suggests that there could be many other extragalactic exoplanets waiting to be discovered. However, the chances of it being confirmed in the next 70 years are slim.
But it is not the first time potential planets have been reported in other galaxies. The object, which is roughly the size of Saturn, orbits around a massive star and a smaller dense core of a dead star known as a neutron star, or a black hole. As it passed in front of its binary stars, it caused a dip in X-ray emissions produced by the neutron star or black hole sucking gas off its companion. The transit lasted about three hours.
Astronomers use dips in visible light, known as the transit method, to detect alien planets in our own galaxy. But the team said using X-rays could allow them to find objects that are hard to spot.
But while the team say they’ve picked up tantalising hints of a potential planet, much more work will be needed to confirm if it is one, and not a patch of dust. That’s because the potential planet takes 70 years to orbit its suns, travelling at a distance that is twice that of Saturn to our sun. For us to see it, it would also have to line up in the right position, at the right time. The only confirmed planets that we’ve spotted within our own galaxy, the Milky Way, have orbits of around 10 years. To make things even harder, it is extremely difficult to spot objects orbiting binary targets blasting off high energy.