Study hypothesizes why some black holes are not actually black

Researchers from Duke University and the University of Cambridge have hypothesized in a new study that some black holes are not actually black.

Washington, Sept 25 : Researchers from Duke University and the University of Cambridge have hypothesized in a new study that some black holes are not actually black.

Albert Einstein originally theorized that stars bigger than the Sun can collapse and compress into singularities, entities so confining and massively dense that the laws of physics break down inside them.

Astronomers have since found indirect evidence for these entities, which are popularly known as black holes, named so because light does not escape from them and they appear perpetually black to the rest of the universe.

However, despite the general support for the universality of black holes, Kip Thorne and John Preskill, two experts in the cosmology of relativity at the California Institute of Technology, have suggested for more than a decade that naked singularities could exist in certain instances.

Now, Arlie Petters and Marcus Werner have devised a way to test for their presence.

As part of their study, the pair employed a theory that a black hole could be shed of its event horizon and become a naked singularity if its angular momentum - an effect of its spin being greater than its mass.

Petters said, as astronomers cannot say for sure whether all black holes are actually black, having never fully penetrated the obscuring outward matter surrounding such objects; therefore as evidence, they can only point to effects that the massive gravitational pull of certain unseen entities exert on surrounding matter.

He said those effects include emissions of highly energetic radiation, or the extreme orbits of nearby stars.

The team generalized an application of gravitational lensing to all realistic spinning singularities and found that a black hole weighing about 10 times more than our Sun would spin a few thousands rotations a second.

They said their calculations showed that a naked singularity's massive gravitation would split the light of background stars or galaxies in telltale ways that are potentially detectable by astronomers using existing or soon-to-be instruments.

"If you ask me whether I believe that naked singularities exist, I will tell you that I'm sitting on the fence. In a sense, I hope they are not there. I would prefer to have covered-up black holes. But I'm still open-minded enough to entertain the 'otherwise' possibility," said Petters.

The findings appear online in the September 24 issue of the journal Physical Review D.

ANI