Astronomers have long known that when binary star systems wander too close to a supermassive black hole under the right conditions, they can be torn apart in such a way that one star is pulled into orbit around the black hole and the other is violently ejected outward, sending it speeding out of the galaxy and into interstellar space. Now it turns out individual planets can suffer a similar fate - and when they do, they can do so at up to 50 million kilometres per hour, making them some of the fastest-moving objects in our galaxy.

A mournful French horn blows. An angsty Luke Skywalker stomps out of his aunt and uncle's sand hut and peers up at Tatooine's double sunset, his hair blowing in the breeze. It's a memorable scene from Star Wars-but now, a precedent for such a sky with two suns has been found in our universe.