A Bombay scientist has sought to disprove the existence of ‘black holes’ in the universe — the concept that fascinated physicists for more than 200 years.

Dr Abhas Mitra, a senior scientist and an astrophysicst of Theoretical Physics Division of the Bhabha Atomic Research Centre in Bombay, claimed that he has disproved the concept of black holes, which are supposed to be objects so compact that from which even light can not escape.

Mitra has pointed out in his paper, ‘Non-occurrence of trapped surfaces and black holes in spherical gravitational collapse’ in the current issue of the journal ‘Foundations of Physics Letters’ that just removing the ‘subtle errors’ in the earlier work of famous physicists J R Oppenheimer and H Snyder had led to the ‘rejection’ of formation of black holes.

Mitra claimed that his results could help in understanding several currently unexplained astrophysical phenomena including cosmic gamma ray bursts.

Mitra has also shown that one of the crucial assumptions made by the renowned scientists like Stephen Hawking and Roger Penrose and others that of formation of ‘trapped surface’ which traps light is actually not allowed by Albert Einstein’s generalised collapse equation as the local speed of the collapsing fluid ‘does not exceed the speed of light’.

Mitra said he has reconfirmed Einstein’s results from two different considerations –the first being the GCE and the second the behaviour of material particle which acts like a photon (light) on the so called event horizon, the boundary of supposed black hole.

Mitra said with his results it may be easier to understand many observed astrophysical phenomena.

Mitra’s paper has shown that the presence of physical surfaces endowed with magnetic fields help in understanding phenomenon such as ‘jets’ found to be ejected from many galactic centres or stellar mass comapct objects.

He said since the finite mass or black holes suggested by many physicists has no magnetic field many cosmic phenomena are not properly understood using black hole paradigm.

However, Mitra has suggested that the eternally collapsing objects (astroballs) in the universe have a large to ultra high magnetic field which may help in clearing several queries of the astrophysicsts.

One of the early proponents of the idea of black holes was the French mathematician P S Laplace and the modern concept of black holes is supposed to have been consolidated by the work of American physicists Oppenheimer and Snyder who studied in 1939 the collapse of a highly idealised fluid ball having no pressure and density gradient.

Then in 1960s, Hawking, Penrose and others formed the so-called singularity theory which further consolidated the notion of black holes.

Mitra has further pointed out that irrespective of the correctness of his main derivatives, the derivations using Kruskal coordinates and ordinary or Schwarchild coordinates had revealed that there cannot be any finite mass black hole and technically, the EH itself must be the singularity of a zero mass black hole.

Quoting Einstein’s general theory of relativity that space-time is like a rubber sheet which gets stretched due to the presence of massive bodies or any other form of energy, Mitra explained that ‘zero mass black hole state is never realised in any finite time’.

As the body collapses, its tidal gravitational pull tends to become infinite even though its gravitational mass decreases due to emission of radiation, Mitra said adding that the GTR as singularity free was always cherished by Einstein.

“Einstein never believed in the existence of black holes and most of his peers and proponents of black holes thought that Einstein was unable to fully appreciate his own theory,” Mitra added.

(Copyright 2000 PTI)

Source:

http://www.rediff.com/news/2000/dec/22barc.htm