We now know that a third black hole is created when two black holes merge because of gravitational wave observatories. Due to the energy dissipated in the form of gravitational waves, the resulting black hole is slightly less massive than the sum of its parents. This third and final black hole is also ejected from its point of origin due to the time-space distortion that gave rise to it. The speed with which this recoil can occur has now been recreated by scientists.
The behavior of black holes in high-energy collisions was studied using 1,381 simulations. They determined that the combined black hole may be propelled into space at a speed of around 28,600 kilometers (17,800 miles) per second under ideal conditions. A really swift black hole, indeed.
We calculated how fast the merged black hole could go after it was created from two colliding black holes. “We found a maximum that is about 10 percent of the speed of light, which is very fast for astrophysical standards,” co-author Professor Carlos Lousto from the Rochester Institute of Technology told IFLScience.
The collision won’t eject all black holes at such a high velocity. The researchers learned that hitting that top speed requires meeting a long list of criteria. In the simulation, the black holes that are combined are supposed to be spinning in opposing directions.
When it comes to the path they take around one another before they crash into one another, they are also on the same side. These artificial black holes are inclined, resembling Earth’s orbit around the Sun. In contrast to the 23.5-degree tilt of Earth, these hypothetical black holes are angled at 90 degrees and facing in opposite directions.
Professor Lousto told IFLScience, “The spins — how fast they are rotating on their axis — and the orientation are the most crucial aspect.” It appears to be quite important that [the spin directions] lie on the same plane as the orbit. For maximum anisotropy, both spins within the orbital plane should point in the opposite direction from one another. This causes the most extreme form of asymmetric radiation, which in turn causes the recoil.
This recoil is so powerful because of the release of gravitational energy. The dramatic nature of black hole encounters causes some of the mass to be converted into gravitational waves. Recoil can be improved by emitting in an asymmetrical pattern. The researchers, however, were also interested in knowing the limit of how much energy may be extracted from a black hole collision.
Preliminary results from their new work, which Professor Lousto was able to share with us, suggest that, under optimal conditions (quite different from the maximum recoil), up to 27% of the black holes’ mass can be converted into gravitational waves.