Nothing can escape from a black hole, not even light. In simple words, they are the regions of space with an extremely strong gravitational field. But we can see the effects that black holes have on the space around them.
Black holes remain one of the most mysterious objects in the universe. Understanding them and how they become supermassive could help astronomers determine the evolution of the universe.
To explain the formation of supermassive black holes and the nature of dark matter, three physicists at the US Department of Energy’s (DOE) Brookhaven National Laboratory have recently developed a model for a dark sector of the universe. Their study explained the cosmological phase transition that allows supermassive black holes to form in a dark sector of the universe.
Theoretical physicist Peter Denton said: “Before there were galaxies, the universe was hot and dense, and that is well established. How the universe cooled down to what we observe today is a topic of interest because we have no experimental data describing how that happened. We can predict what happened to the known particles because they frequently interact. But what if there are as-yet-unknown particles that work differently?
To find the answer, scientists developed a model to explore the dark sector of the universe, where as-yet-undiscovered particles abound and rarely interact. The frequency of known particle interactions suggests that matter as we know it would not have collapsed into black holes very efficiently.
Denton said, “But if there was a dark sector with ultralight dark matter, the first universe might have had the right conditions for a very efficient way of collapsing.”
Scientists know that black holes acquire mass by two main means: 1. Accretion, in which matter, mainly dust, falls into black holes. 2. Galactic collisions, during which two black holes can merge.
However, in the early universe, galaxies were in their infancy. So scientists wondered how these ancient cosmological wonders got so massive so quickly. Ultralight dark matter particles could be the missing piece.
Dentón said, “We theorized how particles in the dark sector might undergo a phase transition that allows matter to very efficiently collapse into black holes. When the temperature of the universe is just right, the pressure can suddenly drop to a very low level, allowing gravity to take over and matter to collapse. Our understanding of known particles indicates that this process would not normally happen.”
“Such a phase transition would be a dramatic event, even for something as spectacular as the universe.”
“These collapses are a big problem. They emit gravitational waves. Those waves have a characteristic shape, so we make a prediction for that signal and its expected frequency range.”
Hooman Davoudiasl et al. Supermassive black holes, ultralight dark matter, and gravitational waves of a first-order phase transition. DOI: 10.1103/PhysRevLett.128.081101