But to confirm it, astronomers would need to measure how much rotational energy is lost by the black hole, which is difficult. Similarly, measuring the amount of magnetic “flux” from accretion disk material that passes over the event horizon would give an estimate of rotational energy loss, but this is also difficult to measure. Now, Nokhrina’s new model — and other recent, more advanced models of black hole jets — suggests a proxy: measuring the magnetic field of the jets, which can then be tied into the amount of rotational energy required to power them.The jets' magnetic field can be measured, and “because the magnetic flux is conserved, by measuring its magnitude in the jet, we also learn the magnetic flux near the black hole,” said Nokhrina in a press release . Her work now allows astronomers to connect the magnetic field of jets to the rotation lost by the black hole, and test experimentally whether our understanding of how black holes and the disks and jets around them behave is correct, or still needs further refinement.All this comes just months before the expected release of the results from the Event Horizon Telescope , a worldwide network of facilities that in April 2017 spent a week and a half gathering data on the Milky Way's supermassive black hole, as well as the huge black hole in the elliptical galaxy M87. Soon we may have the first image of not only the torus around a supermassive black hole, but the edge of a black hole's event horizon itself. It's certainly an exciting time to be an astrophysicist.