New research suggests that we may soon be able to test one of Stephen Hawking’s most controversial theories.
Now, three astronomers have developed a theory that explains not only the existence of dark matter, but also the appearance of the largest black holes in the universe.
“What I personally find very exciting about this idea is how elegantly it unites the two challenging problems I work on, which are exploring the nature of dark matter and the formation and growth of black holes, and solving them all at once.” With study author Priyamvada Natarajan, Yale University astrophysicist, He said in a statement. In addition, several new instruments, including the recently launched James Webb Space Telescope, can produce the data needed to finally evaluate Hawking’s famous idea.
Black holes from the start
Dark matter makes up more than 80% of all matter in the universe, but it doesn’t interact directly with light at all. It floats greatly, affecting gravity within galaxies.
It’s tempting to think that black holes could be responsible for these elusive things. After all, black holes are poorly dark, so filling the galaxy with black holes could theoretically explain all observations of dark matter.
Unfortunately, in the modern universe, black holes form only after massive stars die and then collapse under the weight of their own gravity. So making black holes takes a lot of stars, which takes a lot of ordinary matter. Scientists know how much natural matter there is in the universe from calculations made in the beginnings of the universe, as the first was hydrogen s Helio formed. Nor is there enough natural matter to make all the dark matter that astronomers have observed.
This is where Hawking came in. In 1971, it was suggested that black holes formed in the chaotic environment of the first moments of the Big Bang. There, foci of matter could spontaneously reach the densities needed to create black holes, flooding the universe with them long before the first stars shined. Hawking suggested that these “primary” black holes may be responsible for the dark matter. While the idea was intriguing, most astrophysicists focused on finding a new subatomic particle to explain dark matter.
Furthermore, prototypes of black hole formation have included observational problems. If many of them formed in the early universe, they changed the picture of the remaining radiation from the early universe, known as the cosmic background radiation (CMB). This means that the theory only works when the number and size of ancient black holes are very limited, or they conflict with CMB measurements. .
The idea was revived in 2015, when the Laser Interferometer Gravitational-Wave Observatory found the first pair of colliding black holes. The two black holes were much larger than expected, and one way to explain their enormous mass was to say that they formed early in the universe, not in the hearts of dying stars.
In the latest research, Natarajan and Niko Capilotti of the University of Miami and Gunther Hesinger of the European Space Agency delve into the theory of primordial black holes, exploring how they can explain dark matter and possibly solve other cosmic challenges.
To pass current observing tests, primordial black holes must be within a certain mass range. In the new work, the researchers hypothesized that primordial black holes had a mass about 1.4 times the mass of the Sun. They built a model of the universe that replaced all the dark matter with these bright black holes, and then looked for observational evidence that could validate (or rule out) the model.
The team discovered that primordial black holes could play an important role in the universe, nurturing the first stars, the first galaxies, and the first supermassive black holes (SMBHs). Observations indicate that stars, galaxies, and SMBHs appear very quickly in cosmic history, perhaps too fast to be explained by the formation and growth processes we observe in the universe today.
“Primary black holes, if they exist, may be the seeds from which all supermassive black holes, including those in the center of the planet, are formed. Milky WayNatarajan said.
The theory is simple and does not require a garden of new particles to explain dark matter.
“Our study shows that without introducing new particles or new physics, we can solve the mysteries of modern cosmology, from the nature of dark matter itself to the origin of supermassive black holes,” Capelloti said in the statement.
So far this idea is just a prototype, but it can be tested relatively soon. The James Webb Space Telescope, launched on Christmas Day after years of delays, was 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 about to reveal more about black holes, including primordial holes, if they exist.
Together, the two observatories should provide astronomers with enough information to reconstruct the history of the first stars, and possibly the origin of dark matter.
“It was irresistible to explore this idea in depth, knowing that it would likely be validated soon,” Natarajan said.
Originally published in Live Science.
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