How many black holes are known to exists at the time

As of my knowledge cut off in 2 0 2 1 , there is no definit ive answer to the number of black holes that exist in the universe . Black holes are formed when a star col laps es at the end of its life , and they are not difficult to detect due to their small size and the fact that they do not emit much light . \n \n However , astronom ers have observed many objects that are thought to be black holes , including super mass ive black holes at the cent ers of galaxies and smaller black holes in binary star systems . It is estimated that there are millions of black holes in our own Mil ky Way galax y alone , but this is just an estimate based on observations of other galaxies and the properties of stars black holes . \n \n It ' s also worth not ing that the number of black holes in the universe could change over time as new ones are formed and others may ev apor ate or merge with other black holes . </s>