Another type of black hole is formed upon extreme compression of matter by external forces. This type of black hole is considered a primordial black hole. Additionally, this type of black hole is allowed to have mass less than the sun, since it was not created by the collapse of a star.

One possibility of the existence of such black holes are during the early stages of the universe where high temperatures and pressures existed (Hawking 127).

The existence of primordial black holes may also help explain the missing hydrogen and helium that theorists predicted should exist based on calculations of expansion and cooling of the universe after the Big Bang. According to Sasaki and Umemura from the Tokyo Metropolitan University, a great number of black holes with about 100,000 solar masses each would have existed in the early stages of the universe. These black holes could have consumed greater amounts of the gases earlier and then vanished under the event horizon when there was no more gas to consume (First Holes 29-30).