Over the last 15 years, astronomers have detected nearly 500 planets orbiting stars in our cosmic neighbourhood, but none outside our Milky Way has been confirmed [1]. Now, however, a planet with a minimum mass 1.25 times that of Jupiter [2] has been discovered orbiting a star of extragalactic origin, even though the star now finds itself within our own galaxy. It is part of the so-called Helmi stream -- a group of stars that originally belonged to a dwarf galaxy that was devoured by our galaxy, the Milky Way, in an act of galactic cannibalism about six to nine billion years ago.

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