One-Hour Light Bender Hints at Primordial Black Hole in Milky Way Halo

A star in the Large Magellanic Cloud briefly brightened for about an hour in 2019 due to gravitational microlensing by an unseen object nicknamed Phoebe. Its mass is estimated at roughly three lunar masses, too light to be a planet or stellar black hole. Analyses favor Phoebe being a dark-matter object in the Milky Way halo, with a primordial black hole as a leading exotic possibility; if confirmed, it would be among the oldest objects in the universe. Alternatives include a free-floating planet in the Milky Way or in the LMC. The event highlights microlensing as a tool to probe dark matter and compact objects.