Black holes are hard to fully understand. Every time I learn more about them, I feel like I understand them less. The basic idea is simple: if the mass inside a volume gets high enough, the escape velocity becomes larger than the speed of light. 

Earth is a people hole since its gravity prevents me from jumping off, but at its current size, light can fly away, no big deal. Now, if you mash the Earth’s mass down to about half an inch across, that much mass in that small space is totally going to be a black hole. While stuff can’t escape a black hole, forces like gravity can totally be felt across that event horizon, and calculating the tangled relationships between a black hole and any surrounding material requires understanding gravity, magnetic fields, and all of the relativistic versions of both.

From looking at black holes, we know cool stuff is happening. Some systems flare up on a regular basis, including the supermassive black hole in our own galaxy, which flares daily in high-energy light. We just didn’t know why. Until now.

In new research published in The Astrophysical Journal and led by Bart Ripperda, researchers show how magnetic field lines can pile up, tangle, and ultimately reconnect with a release of energy on a regular basis. As described in the release: …new simulations show that interactions between the magnetic field and material falling into the black hole’s maw cause the field to compress, flatten, break and reconnect. That process ultimately uses magnetic energy to slingshot hot plasma particles at near light speed into the black hole or out into space.

And when those particles fly out, they trigger those flares we see.

This research was only possible thanks to the combined power of three supercomputers that increased model resolution by a factor of 5,000. According to Ripperda: Without the high resolution of our simulations, you couldn’t capture the subdynamics and the substructures. In the low-resolution models, reconnection doesn’t occur, so there’s no mechanism that could accelerate particles.

Sometimes, the answer actually is to enhance, enhance, enhance.

More Information

Simons Foundation press release

“Black Hole Flares: Ejection of Accreted Magnetic Flux through 3D Plasmoid-mediated Reconnection,” B. Ripperda et al., 2022 January 14, The Astrophysical Journal Letters