Black holes DO exist

Apiece in The Daily Mail reports the conclusion of Laura Mersini-Houghton, a cosmologist and a theoretical physicist at the University of North Carolina, that black holes do not exist.

In order to understand what led Mersini-Houghton to make such an earth-shattering claim, it is necessary to have a brief understanding of the history of black holes. A black hole -- one of Einstein's general relativity's predictions -- is an unfathomable hole drilled in the superstructure of the Universe. Inside a black hole, the immense strength of gravity distorts the structure of space and time so severely that light rays can no longer travel in a straight line, but rather follow a trajectory curving back towards the black hole. Consequently, light rays remain trapped, resulting in a total information blackout.

But according to the uncertainty principle of quantum mechanics, information from the Universe can never disappear. Thus we see that when it comes to black holes, quantum theory and Einstein's general relativity fail to agree. This is known as the “information loss paradox.”

In 1974, Stephen Hawking proposed that a black hole temporarily (which could be aeons!) entraps matter and energy that can eventually reemerge as radiation. This outgoing radiation, known as Hawking Radiation, possesses all the original information about what fell into the black hole. The radiation is yet to be detected from a “real” black hole.

Mersini-Haughton agrees that as a star collapses under its own gravity, it produces Hawking Radiation, but before it becomes a black hole and not after, as predicted by Hawking. She claims that by giving off this radiation, a star's mass also decreases. Eventually, the star won't have enough mass to become a black hole. Her calculations indicate that the collapse of a star will stop at a finite radius before the event horizon of a black hole, which is an imaginary boundary beyond which everything is forever hidden.

It should be noted that current cosmological models predict that a star becomes a black hole if its mass is greater than three solar masses. In that case, there is no force in the Universe that can prevent gravity from crushing it into zero volume and infinite density, known as a singularity. Indeed, numerous black holes, including super-massive ones at the centre of galaxies as far as 2.7 billion light years away from Earth, have been detected by the space-based Hubble telescope and the Chandra Observatory.

Through her claim of the nonexistence of black holes, Mersini-Haughton is questioning the validity of the fundamental concept of “singularity” out of which the Universe was born. If she is correct, then the Big Bang Theory is wrong. If Big Bang Theory is correct, then she is wrong.

A scientist's work will gain acceptance if it is published in a high-impact refereed journal. The paper by Laura Mersini-Houghton on the nonexistence of black holes was rejected by the referees of the prestigious journal Physics Letters. The article can be found on arXiv, an online repository of physics papers that is not peer-reviewed.

The physics community, particularly cosmologists and astrophysicists, consider Laura Mersini-Houghton's claim about nonexistence of black holes as nonsense or an outcome of her lack of understanding of Hawking Radiation. I see it as a reenactment of Ponsch and Fleischmann's infamous claim in 1989 that they observed cold fusion in the laboratory.

According to mainstream cosmologists, a black hole doesn't emit enough Hawking Radiation to shrink its mass down to where Mersini-Houghton claims. Hence, there is no evidence to support her hypothesis that there are no black holes.

The writer is Professor of Physics at Fordham University, New York.