Dark Matter and Primordial Black Holes Might be One and The Same
A new model by an international group of researchers suggests that dark matter is hidden within primordial black holes created in the first moments following the Big Bang, a press statement reveals.
The model was created by astrophysicists at Yale University, the University of Miami, and the European Space Agency (ESA). Now, they believe that data from the recently-launched James Webb Space Telescope could prove the model true in a move that would completely alter our understanding of the cosmos.
A 1970s Stephen Hawking theory inspires new dark matter research
Dark matter has only been indirectly observed via enormous amounts of unaccounted-for gravitational force observed throughout the universe and phenomena such as gravitational lensing. Researchers in Italy recently believed they observed direct evidence of dark matter in the form of flashes of light in sodium iodide crystals. However, a team at Yale was unable to reproduce those results casting the original claims into doubt.
The new study by the group of international researchers, published in The Astrophysical Journal, took inspiration from a 1970 theory proposed by physicists Stephen Hawking and Bernard Carr. The two physicists argued that in the first fraction of a second after the Big Bang, minuscule fluctuations might have created "lumpy" regions with extra mass as the universe rapidly expanded. According to the theory, these lumpy regions then collapsed into early primordial black holes.
Though this theory didn't gain a great deal of traction at the time, it has been revived by a new group of scientists with promising results. According to the new paper's theorist, Yale professor of astronomy and physics Priyamvada Natarajan, these primordial black holes could potentially account for all dark matter. However, for that to be true, they must have been "born" measuring approximately 1.4 times the mass of the Earth's sun.
"Primordial black holes, if they do exist, could well be the seeds from which all supermassive black holes form, including the one at the center of the Milky Way," Natarajan said. "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," she added.
The James Webb Telescope holds the key
Natarajan and her team must now wait for observations from the James Webb Telescope, which successfully launched following a long string of delays on Christmas eve. The telescope has the capacity to observe the first galaxies that formed in the early universe as well as stars forming planetary systems.
In the 2030s, a mission involving the ESA's Laser Interferometer Space Antenna (LISA) attached to the James Webb Telescope will be able to prove or disprove the new theory. If primordial black holes account for dark matter, more stars and galaxies will have formed around them in the early universe. The LISA instrument will also be able to detect wave signals from primordial black hole merges that took place in the early days of the universe. All of this means we may be in the extremely rare position of seeing a new theory related to the very early universe validated only within a few years of its proposal.