Scientists have proven one of Albert Einstein's theories, finding evidence that a plunging-region around black holes not only exists, but also exerts some of the strongest gravitational forces yet identified in the galaxy.

Einstein's theory states that it is impossible for particles to safely follow circular orbits when close to a black hole.

Instead, they rapidly plunge toward the object at close to the speed of light, giving the plunging region its name.

Experts say the findings show matter responding to gravity in its "strongest possible form."

The new study focused on this region in depth for the first time, with Oxford University Physics researchers using X-ray data to gain a better understanding of the force generated by black holes.

Andrew Mummery, of Oxford University Physics, who led the study, said: "What's really exciting is that there are many black holes in the galaxy, and we now have a powerful new technique for using them to study the strongest known gravitational fields."

He added: "Einstein's theory predicted that this final plunge would exist, but this is the first time we've been able to demonstrate it happening.

"Think of it like a river turning into a waterfall – hitherto, we have been looking at the river. This is our first sight of the waterfall."

"We believe this represents an exciting new development in the study of black holes, allowing us to investigate this final area around them."

"Only then can we fully understand the gravitational force."

"This final plunge of plasma happens at the very edge of a black hole and shows matter responding to gravity in its strongest possible form."

Researchers say that there has been much debate between astrophysicists for many decades as to whether the so-called plunging region would be detectable.

The Oxford team spent the last couple of years developing models for it. The study just published demonstrates its first confirmed detection found using X-ray telescopes and data from the International Space Station (ISS).

The study, published in the Monthly Notices of the Astronomical Society, focused on smaller black holes relatively close to Earth, using X-ray data gathered from space-based telescopes.

Later this year, a second Oxford team hopes to move closer to filming the first footage of larger, more distant black holes.