A new study has discovered the first known permanent immigrant to our solar system. The asteroid, currently nestling in Jupiter's orbit, is the first known asteroid to have been captured from another star system. The new work is published in the peer-reviewed Monthly Notices of the Royal Astronomical Society: Letters. The object known as 'Oumuamua was the last interstellar interloper to hit the headlines in 2017. However, it was just a tourist passing through, whereas this former exo-asteroid – given the catchy name (514107) 2015 BZ509 – is a long-term resident. All of the planets in our solar system, and the vast majority of other objects as well, travel around the Sun in the same direction. However, 2015 BZ509 is different – it moves in the opposite direction in what is known as a "retrograde" orbit. Fathi Namouni, lead author of the study, said: How the asteroid came to move in this way while sharing Jupiter's orbit has until now been a mystery. If 2015 BZ509 were a