Black holes and dark matter are two of the most fascinating phenomena in the universe. While we know for sure that black holes exist, the story is not as clear cut when it comes to dark matter. The only evidence we have for this unusual substance is circumstantial, but there is a lot of it. Most of it is impossible to explain using any other explanation other than it’s some kind of a particle or some kind of a mass that interacts with everything gravitationally but not through electromagnetic means, which is why it doesn’t produce light and seems to be kind of invisible.
A recent study provides even more evidence for the existence of dark matter as a particle and not some unusual phenomenon or some unusual formula that we don’t understand. The study, titled “Direct evidence for dark matter density spikes around stellar mass objects,” takes a look at old hypotheses regarding dark matter and its relationship to black holes.
The idea is that black holes can sometimes slow down dark matter and increase in mass, which suggests that other mass objects would probably be doing something similar. While the black hole slows down dark matter, some of this dark matter is going to be orbiting around it, with quite a lot of it potentially coming really close to the black hole’s event horizon or assuming orbits around the black hole, possibly even permanent orbits.
Scientists wanted to find out if this is actually what’s happening around two relatively known binary systems, XTE J1118+480 and A0620-00, both containing a black hole and a star in orbit around one another. By taking a lot of data from these two star systems and looking at the changes in the orbital period, the scientists were able to calculate the overall orbital decay for both of these star systems.
The scientists realized that the orbital change was more dramatic than expected. The star decay was slowing down by about one millisecond per year more than it should, and modern theories, including Einstein’s theories, cannot really explain this. The scientists then came up with different models trying to explain what’s happening, including using computer simulations to come up with a model that would try to explain this using what’s known as the dark matter dynamical friction model.
The model considers the presence of dark matter as a potential source for the actual slowdown. In other words, dark matter orbits a black hole, and gravitational pulling at these stars might be the reason why these stars in this binary system are slowing down more than expected.
This study provides exciting new evidence for the existence of dark matter as a particle and not just some unexplained phenomenon. It also shows that scientists are continuing to make progress in understanding the universe’s most mysterious substances. With further research, we may one day unlock the secrets of dark matter and its role in shaping the universe as we know it.