While extragalactic “rogue” planets – not orbiting any star – have been reported before, the new exoplanet is the first to be detected orbiting stars in another galaxy. And not just any galaxy … but M51, the beautiful Whirlpool, 23 million light-years away.

The famous Whirlpool Galaxy (M51) as seen by the Hubble Space Telescope. The new candidate exoplanet, M51-ULS-1b, orbits an unusual binary star system in the galaxy. Image via NASA/ ESA/ S. Beckwith (STScI)/ Hubble Heritage Team (STScI/ AURA).