In new research, scientists analyze how supermassive black holes located at the hearts of many galaxies have influenced the way other black holes form. The spin and gravity generated by these monster black holes can force smaller black holes to coalesce into “jams” that allow them to combine and become larger. In black hole jams there is a part of Mario Kart and another of Katamari Damacy.
Supermassive black holes, like the one at the center of our Milky Way, are millions or even billions the size of our Sun. They are not very well understood, but they are very, very old and inseparable from the galaxies they occupy. . The Milky Way’s supermassive black hole, Sagittarius A*, likely played a role in the formation of the galaxy’s spiral shape with its unfathomable gravity and directional rotational force known as torsion.
Throughout the universe there are “migrating pairs,” that is, places where rotational forces end up moving rogue objects toward the objects that generate the pairs. Flushing a toilet is like a pair of migration down the drain. But these points can be very strong, just as you can create a fun but weak whirlpool in a circular pool by walking around its edges. That won’t flush your toilet, but for a long time, it will collect sediment from a larger general area.
These twists, in space, contribute to the “jams” of black holes. Supermassive black holes, also called active galactic nuclei, have disks of accreted (or accreted) materials orbiting around them. Additionally, each of them has its own global migration pair. Within the accretion disk zone, there are other much smaller black holes – on a stellar scale, rather than on a galaxy scale – and each of them has its own accretion disk. A thermal reaction occurs in which all these accretions mix and apparently greatly increases the distance reached by the original migrating pair. As a result, the researchers call their hypothetical traffic jams “thermal pairs.”
There is a tipping point of various factors at which thermal torques begin to exceed regular gravitational torques within the influence of a supermassive black hole. That turns a migration pair toward the supermassive black hole into a thermal migration pair pointing outward. Something special happens in areas where the pair “flips” in this way, and the researchers suggest it is caused by the collision of accretion disks within the system. Imagine the chaos (and visible turbulence) that would occur if you placed a toilet cistern in the middle of your backyard whirlpool.
Thus, within these torque shifting zones – which, in general, may be more neutral for migration – smaller black holes can be slowed down by forces and then combine. Moving objects are difficult to match, but still objects can be found more easily. Then, they are ready to be swept together by the swirl of the thermal couple and the migration couple.
If breaking down and studying all the overlapping gravities and other galactic-scale forces seems like an overwhelmingly big problem to you, you’re not alone. But scientists choose and study one small aspect at a time. This work, for example, focuses on how thermal torsion and migration torsion affect each other under specific parameters in order to take just one step forward. The team says their work illustrates a good guess about how binary black holes meet and merge.
But this small piece must be woven into the broader, more complex intersections of many other factors, and that’s something the next 5, 25, or 100 teams will need to explore.
Caroline Delbert is a writer, avid reader, and contributing editor at Pop Mech. She’s also an enthusiast of just about everything. Her favorite topics include nuclear energy, cosmology, math of everyday things, and the philosophy of it all.
