Could Black Holes Account for ‘Missing’ Dark Matter?

A new study proposes that black holes formed at the dawn of time may actually account for all dark matter. This theory, the authors note, builds on previous work from Stephen Hawking performed in the 1970s, and may finally answer one of the biggest questions about the origins and nature of the universe.


Few mysteries have flummoxed astronomers and astrophysicists as much as dark matter. That is mainly because the behavior of planets, star systems and even entire galaxies evidence the weighty pull of the stuff. However, just like its name, dark matter has remained particularly elusive to locate.

In an attempt to rectify this imbalance, a team of scientists have proposed a new method for the formation of the universe itself, including an answer to the mystery of dark matter.

black holes dark matter
Image Credit: ESA


“A team of astrophysicists suggests that all black holes—from those as tiny as a pin head to those covering billions of miles—were created instantly after the Big Bang and account for all dark matter,” explains a press release announcing the newly published study. “That’s the implication of a study by astrophysicists at the University of Miami, Yale University, and the European Space Agency that suggests that black holes have existed since the beginning of the universe ­­and that these primordial black holes could be as-of-yet unexplained dark matter.”

“Our study predicts how the early universe would look if, instead of unknown particles, dark matter was made by black holes formed during the Big Bang—as Stephen Hawking suggested in the 1970s,” explained the study’s first author Nico Cappelluti, an assistant professor of physics at the University of Miami. “This would have several important implications.”

First, explained Cappelluti, “We would not need ‘new physics’ to explain dark matter.” Plus, he notes, “this would help us to answer one of the most compelling questions of modern astrophysics: How could supermassive black holes in the early universe have grown so big so fast?”

That conundrum arises from the fact that under current cosmic conditions, black holes shouldn’t be able to form so fast. However, based on the new proposal, those conditions may have been different immediately after the Big Bang.

“This would also solve the long-standing mystery of why the mass of a galaxy is always proportional to the mass of the super massive black hole in its center,” added Cappelluti.

The recently published work follows up on work done in the 1970s by famed researcher Stephen Hawking and physicist Bernard Carr, who proposed that in the moments immediately following the Big Bang, variations in the density in matter led to “lumpy” regions which may have collapsed into black holes. That idea gained little support at the time, but the team behind the latest work says they were able to slightly modify the parameters of Hawking and Carr’s original model to come up with their proposed solution.

“Primordial black holes, if they do exist, could well be the seeds from which all the supermassive black holes form, including the one at the center of the Milky Way,” said Priyamvada Natarajan, one of the paper’s co-authors, and a professor of astronomy and physics at Yale. “What I find personally super exciting about this idea is how it elegantly unifies the two really challenging problems that I work on—that of probing the nature of dark matter and the formation and growth of black holes—and resolves them in one fell swoop.”


According to the release, “the existence of primordial black holes may be proven—or disproven—in the near future.”

That, the researchers note, is thanks to the soon to be launched James Webb Telescope, which can peer back in time to see the light from the earliest days of the universe, when such primordial black holes should have formed.

“If the first stars and galaxies already formed in the so-called ‘dark ages,’ Webb should be able to see evidence of them,” said Günther Hasinger, a director of science at the ESA.

Finally, the team notes that another planned observatory, the ESA’s Laser Interferometer Space Antenna (LISA) mission, which is slated for deployment sometime in the 2030’s, should also be able to confirm these primordial black holes by the signatures of gravitational waves.

Follow and connect with author Christopher Plain on Twitter: @plain_fiction