Due to the significant distance between us, detecting exoplanets outside our own galaxy is extremely difficult. However, these scientists investigated the planet M51-ULS-1 in the galaxy M51 by studying the light curves of its X-ray binaries.

Astrobiology
Charting the Cosmos: the Concept of Kardashev Civilizations
As we gaze upon the universe, contemplating our place in its vast expanse, we grapple with questions about our future.