Due to the space-time strangeness required to form a stable wormhole, some scientists have considered whether certain black holes might actually be wormholes in disguise. Schwarzschild) black holes. More recently, a 2021 study pondered whether active galactic nuclei, or AGN, are actually wormhole mouths rather than supermassive black holes. Long-standing theories have also wondered if black holes could be paired with mirror twins, known as “white holes,” which would together form wormholes. Related Story Do Black Holes Die?