An article published in the journal “Nature Astronomy” reports the identification of a candidate exoplanet in another galaxy, cataloged as M51-ULS-1b. A team of researchers used NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton Space Telescope to examine what could be the transit of a Saturn-sized exoplanet in M51, a pair of galaxies. In the larger of the two galaxies, there’s an ultra-luminous X-ray source consisting of a dead star and a blue supergiant, and the candidate exoplanet orbits them. The first confirmation of an extragalactic exoplanet would be extraordinary but in this case, not all alternative explanations can be completely ruled out.