New research suggests we may soon be able to test one of Stephen Hawking’s most controversial theories.
In the 1970s, Hawking proposed that dark matter, the invisible substance that makes up most of the matter in the universe, can be made from black hole formed in the earliest moments of Large explosions.
Now, three astronomers have developed a theory that not only explains the existence of dark matter but also the appearance of the largest black holes in the universe.
“What I personally find incredibly exciting about this idea is how it elegantly unifies two really challenging problems that I’m working on – the exploration of the nature of dark matter and the formation of dark matter. formation and growth of black holes – and resolving them in one fall,” said study co-author Priyamvada Natarajan, an astrophysicist at Yale University, said in a statement. Furthermore, several new tools – including James Webb . Space Telescope just launched – could generate the data needed to ultimately evaluate Hawking’s famous concept.
Black hole from the beginning
Dark matter makes up more than 80% of all matter in the universe, but it doesn’t interact with light directly in any way. It just floats around hugely, affecting Gravitation in galaxies.
It’s fascinating to think that black holes might be responsible for this elusive thing. After all, black holes are notoriously dark, so filling a galaxy with black holes could theoretically explain all observations of dark matter.
Unfortunately, in the modern universe, black holes only form after massive stars die, then collapse under the weight of their own gravity. So creating black holes requires many stars – which requires a bunch of normal matter. Scientists know how much normal matter is in the universe from calculations of the early universe, where first hydrogen and helium formed. And there simply isn’t enough normal matter to make up all the dark matter that astronomers observe.
That’s where Hawking comes in. In 1971, he suggested that black holes form in the chaotic environment of the earliest moments of the Big Bang. There, vesicles of matter can naturally reach the density needed to create black holes, flooding them in the universe before the first stars twinkle. Hawking suggested that these “primordial” black holes could be the cause of dark matter. While the idea is exciting, most astrophysicists are focused on finding a new subatomic particle to explain dark matter.
Furthermore, models of primordial black hole formation suffer from observational problems. If too many formed in the early universe, they would change the picture of radiation left over from the early universe, known as the cosmic microwave background (CMB). That means the theory only works when the number and size of ancient black holes is quite limited, or it would contradict the CMB’s measurements. .
This idea was revived in 2015 when the Laser Interferometer Gravitational-Wave Observatory found its first pair of colliding black holes. The two black holes are much larger than expected, and one way to explain their massive mass is to say that they formed in the early universe, not in the hearts of dying stars.
A simple solution
In the latest study, Natarajan, Nico Cappelluti at the University of Miami and Günther Hasinger at the European Space Agency delve into the theory of primordial black holes, discovering how they can explain dark matter and have can solve other cosmic challenges.
To pass current observational tests, primordial black holes must be within a certain mass range. In the new study, the researchers hypothesized that primordial black holes are about 1.4 times the mass of the sun. They built a model of the universe that replaced all dark matter with these rather light black holes, and then they searched for observational clues that could confirm (or rule out) the model.
The team discovered that primordial black holes could play an important role in the universe by seeding the first stars, first galaxies, and first supermassive black holes (SMBHs). Observations indicate that stars, galaxies, and SMBHs appeared very quickly in the history of the universe, perhaps too quickly compared with the formation and growth processes we observe in the universe today.
“Primary black holes, if they exist, could well be the seeds from which all supermassive black holes form, including the one at the center of the universe.” Galaxy,” said Natarajan.
And the theory is simple, and it doesn’t take a zoo of particles to explain dark matter.
“Our work shows that without introducing new particles or new physics, we can solve the mysteries of modern cosmology from the nature of dark matter to the origin,” said Cappelluti. of supermassive black holes”.
So far, the idea is just a mock-up, but it could be tested relatively soon. The James Webb Space Telescope, launched on Christmas Day after years of delay, is specifically designed to answer questions about the origins of stars and galaxies. And the next generation of gravitational wave detectors, especially the Laser Interferometer Space Antenna (LISA), is poised to reveal even more about black holes, including the original ones if they were to be discovered. exist.
Together, the two observatories will provide astronomers with enough information to piece together the story of the first stars and potentially the source of dark matter.
“It was irresistible to explore this idea in depth, knowing it has the potential to be confirmed pretty soon,” says Natarajan.
Originally published on Live Science.
https://www.space.com/testable-primordial-black-holes-theory We can finally test one of Stephen Hawking’s most far-fetched ideas