Research on gravitational waves is still in its infancy. Observations of them only happened in the last few years, and they were possible thanks to several decades of theoretical work behind them. This means theoretical papers on gravitational waves are always exciting and full of potential, even though they might not truly describe something that is possible.
A recent paper, yet to be peer-reviewed, has looked at gravitational waves that, if they were to interact, would form a black hole. These are not waves we have encountered before – for example, if regular objects like neutron stars were to collide, they would form spherical waves, which we can detect. Instead, the ones in the study are flat gravitational waves.
These waves move forward like a tidal wave and are created by an object moving at the speed of light. Frans Pretorius at Princeton University and William East at the Perimeter Institute for Theoretical Physics wanted to know what would happen if two of these flat waves slammed into each other. At low energies, they would just go through one another like nothing happened. But at higher energies, things get interesting.
“These particles have a lot of energy and produce curvature in space-time, and when the waves collide, that curvature wraps in on itself,” Pretorius told New Scientist. “Space-time is sort of sucking itself into a black hole.”
The simulation suggests that 85 percent of the original energy in the waves would be converted into a black hole, with the remaining 15 percent emitted as (much weaker) spherical gravitational waves. However, the creation of such an object would require incredibly powerful waves, nothing compared to what we see.
The LIGO and VIRGO facilities detect gravitational waves by measuring minuscule changes in space-time. A regular gravitational wave squeezes space-time by a fraction of an atom. On the other hand, waves that could create a black hole would be so powerful that they could squeeze space-time by kilometers. We wouldn’t have to worry about them creating a black hole, as they would stretch Earth by thousands of kilometers.
However, if you wanted to create such a wave (maybe you’re a supervillain, we are not judging), you would need to have a particle accelerator bigger than the entire Solar System. So, you know, it’s unlikely that this is going to happen.
[H/T: New Scientist]