Study proves black holes have a ‘plunging region,’ just as Einstein predicted

A recent study has confirmed Albert Einstein's prediction of a "plunging region" at the edge of black holes, where matter can no longer stay in orbit and is inevitably drawn into the black hole. This significant finding was made possible by advanced X-ray telescopes and was detailed in a publication in the "Monthly Notices of the Royal Astronomical Society."

The research, led by Andrew Mummery from the University of Oxford, used NASA's NuSTAR (Nuclear Spectroscopic Telescope Array) and NICER (Neutron star Interior Composition Explorer) telescopes to observe a black hole in the system MAXI J1820+070, located about 10,000 light-years from Earth. The black hole, which is approximately 7 to 8 times the mass of the Sun, is part of a binary system with a smaller companion star. These instruments helped detect how the hot gas, or plasma, from the star is drawn into the black hole, illuminating the previously unobserved "plunging region."

In this region, unlike the event horizon where nothing can escape, light can still escape even though matter is inexorably pulled in by the black hole's gravity. This discovery sheds light on the dynamics at the very edge of black holes, providing crucial insights into their formation and evolution.

The concept of the "plunging region" can be visualized as the edge of a waterfall, where stable, orbiting material abruptly loses its support and crashes into the black hole. This analogy helps to distinguish it from the event horizon, which is closer to the black hole's center and from which no light or radiation can escape.

The study's results have significant implications for astrophysics, allowing scientists to refine models of how matter behaves around black holes. This includes potentially measuring the rotation rates of black holes, which is a critical aspect of understanding their physics.

Christopher Reynolds from the University of Maryland and Dan Wilkins from Stanford University, both not involved in the study, highlighted the importance of this discovery. Reynolds noted that it will significantly enhance models of black hole behavior, while Wilkins pointed out that the study's calculations align with observations of a bright outburst of X-rays in 2018, believed to be from a similar plunging region.

Looking ahead, researchers are developing even more sophisticated tools to study black holes. An Oxford team is working on creating the first movie of a black hole by building the Africa Millimetre Telescope in Namibia. This telescope will join the Event Horizon Telescope collaboration, which famously captured the first image of a black hole in 2019, and will allow scientists to observe and film black holes in unprecedented detail.

This breakthrough underscores the enduring accuracy of Einstein's general relativity and opens new avenues for exploring the extreme environments around black holes, promising exciting developments in the field over the coming decade.