Black holes or balls of Quark Gluon plasma?
doi:10.1038/nindia.2010.35 Published online 1 April 2010
Indian theoretical astrophysicist Abhas Mitra who has been questioning the existence of black holes (BHs) says his theory — contrary to the likely misinterpretation — is really "not in conflict with the basic mathematical notion of BH."
A black hole, according to its advocates, results from gravitational collapse of a massive star. Its pull of gravity is so strong that nothing — not even light — can escape. It is surrounded by an imaginary boundary called the 'event horizon' that shuts everything within.
But Mitra at the Bhabha Atomic Research Centre in Mumbai had been arguing that under Einstein's general theory of relativity gravitational collapse of a star cannot result in a finite mass BH as defined.
The radiation emitted by the collapsing star would get trapped by its ever increasing self-gravity and ultimately the outward pressure of this trapped radiation would counter balance the inward pull of gravity arresting the catastrophic collapse. This, Mitra says, is 'akin to a leaking balloon whose contraction stops as self-gravity plugs the leak by forcing the molecules of the gas to move in closed circular orbits.'
What results, according to Mitra, is not a true BH but a 'radiation pressure supported extremely relativistic star (RRPSS).' Incidentally, noted astrophysicists Sir Fred Hoyle and Nobel laureate William Fowler had shown in 1963 that there could be stars supported entirely by radiation pressure rather than by gas pressure.
Mitra claims that the RRPSS proposed by him is the relativistic version of such radiation pressure supported stars of Hoyle and Fowler. Mitra nicknamed this as an 'Eternally Collapsing Object' (ECO) to signify its steady shrinking indefinitely without ever achieving BH's point like singularity. The so called Black Hole Candidates (BHCs) regularly observed by astronomers as compact objects in many X-ray binaries and central objects in many quasars are nothing but ECOs, he says.
In his latest paper co-authored with Norman Glendenning of Lawrence Berkeley National Laboratory in the United States, Mitra has shown that the RRPSS generated during gravitational collapse of a massive star is 'an intermediate stage' before a true black hole state is formed asymptotically.
"Thus the scenario considered (in our paper) in no way denies that, mathematically, the final state of continued gravitational collapse is a BH," Mitra told Nature India. The researchers further show that the BHCs are actually extremely hot balls of exotic Quark Gluon Plasma — a molten state of neutrons and protons.
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- Mitra, A. Radiation pressure supported stars in Einstein gravity: eternally collapsing objects. Mon. Not. R. Astron. Soc. 369, 492 (2006) | Article
- Mitra, A. et al. Likely formation of general relativistic radiation pressure supported stars or 'eternally collapsing objects'. Mon. Not. R. Astron. Soc. doi: 10.1111/j.1745-3933.2010.00833.x (2010) 10.1111/j.1745-3933.2010.00833.x