Supermassive black holes can render exoplanets uninhabitable at great distances

Reflection on the habitability of exoplanets mainly concerns the distance between a planet and its star. Too close, and any surface water evaporates into space. Too far, the surface waters are frozen. These two situations constitute serious limits to life prospects. Habitability depends on whether an exoplanet is in the Goldilocks zone, a range of distance around a star where liquid water can persist.