Abhas Mitra
| Abhas Mitra | |
|---|---|
| Native name | আভাস মিত্র |
| Born | 18 June 1955 India |
| 🎓 Alma mater | |
| 💼 Occupation | |
Abhas Mitra (born 18 June 1955) is an Indian astrophysicist best known for his unconventional views on astrophysics, particularly related to black holes[1][2][3] and Big Bang cosmology involving the black hole information paradox.[4][5]
Mitra has regularly questioned the mainstream cosmological concepts of the Big Bang and black holes.[6][7][8] He asserts that objects formed from gravitational collapse cannot be true black holes even within the context of classical general relativity and that the Big Bang solution is illusory and actual universe must be fundamentally different.[9][10] His research claims that because of this, dark energy is an illusion caused by the departure of the complex universe from the simple Big Bang model.
Education and career[edit]
He is an alumnus of the Uttarpara Govt. High School, and the University of Calcutta. He did a part of his PhD work at the University of Kashmir before transferring because of armed insurgency that had erupted in Kashmir. The University of Mumbai conferred upon him the status of a "Distinguished Alumnus".[citation needed]
Mitra is associated with the Himalayan Gamma Ray Observatory[11] being set up at Han Leh jointly by Tata Institute of Fundamental Research, Bhabha Atomic Research Centre, and Indian Institute of Astrophysics. He is also an adjunct professor in Homi Bhabha National Science Institute since 2010 and a member of the International Astronomical Union.[12][13]
Scientific work[edit]
Eternally collapsing objects[edit]
Though Mitra stresses that the black hole solutions are correct, he claims that black hole masses, arising from relevant integration constants, are actually zero.[14]. If so, he claims, massive Black Hole Candidates (BHCs) must be quasi-black holes rather than exact black holes and the entire mass energy and angular momentum of gravitationally collapsing objects must be radiated away before formation of exact mathematical black holes.
According to Mitra, since the formation of a mathematical zero mass black hole requires infinite proper time, continued gravitational collapse becomes eternal, and the so-called black hole candidates must be eternally collapsing objects (ECOs).[15][16] Mitra's papers describe why continued physical gravitational collapse should lead to formation of ECOs rather than true black holes, and the mathematical "black hole" states can be achieved only asymptotically.[17][18][19] An ECO is essentially a quasi-stable ultra-compact ball of plasma which is so hot due to preceding gravitational contraction that its outward radiation pressure balances its inward pull of gravity. Mitra is not alone in this conclusion: Robertson and Leiter (2002)[20] reached a similar conclusion in their introduction of the concept of a magnetospheric eternally collapsing object as an alternative to the black hole model.
In 2014, soon after Stephen Hawking called the alleged loss of information in black holes his "biggest blunder",[21] Mitra received widespread attention in the Indian media, claiming that he had been "vindicated",[22][23][24] citing that he had apparently refuted Hawking and indicated the same almost 13 years back.[25][26]
Against the Big Bang paradigm[edit]
As per the present version of Big Bang paradigm, almost 70% of the mass energy of the universe is due to dark energy whose most likely form is Einstein's cosmological constant. Mitra claims that the cosmological constant is exactly zero.[27][28][29][30]
According to Mitra, a Big Bang universe can expand only linearly;[31][32] therefore, popular inflationary and cyclic models are actually inconsistent.
Since perfect Hubble flow implies radially outward motion of Test particles receding from one another without any mutual collision, he claimed his research showed that ideal Big Bang model corresponds to zero pressure and temperature. If correct, this implies that the ideal Big Bang model is fundamentally unable to describe the physical universe endowed with pressure and temperature.[33]
He has also questioned the physical reality of dark energy.[34]
Claimed confirmation of his prediction[edit]
According to Mitra, black holes are actually ultra-magnetized and ultra-hot balls of plasma, nicknamed magnetospheric eternally collapsing objects (MECOs) which are something like extremely general relativistic versions of the Sun. He claims, accordingly, MECOs can give rise to flares like solar flares and Coronal mass ejections like the Sun. And on 25 October 2015, NASA reported that its NuStar telescope has detected a massive X-ray flare from a supermassive black hole in a certain quasar, and this flare appears to be triggered by emission of corona from very close to the black hole.[35] In an interview to Nature India, Mitra claimed that, emission of such a corona from the so-called black hole suggests that it is actually a MECO and not a true mathematical black hole.[36][37][38] In an international workshop entitled "Jet Triggering Mechanisms in Black Hole Sources", organized by Tata Institute of Fundamental Research, Mumbai, India (20–23 January 2016), Mitra elaborated on this point in the presence of large number of astrophysicists.[39]
References[edit]
- ↑ "No Black Hole According To General Relativity?". Nature India.
- ↑ "Anti-black hole astrophysicist furnishes proof". Nature India. 2009. doi:10.1038/nindia.2009.130.
- ↑ "Black holes or balls of Quark Gluon plasma?". Nature India. 2010. doi:10.1038/nindia.2010.35.
- ↑ "Indian Physicist Questions Big Bang Basics". Nature India. 2012. doi:10.1038/nindia.2012.181.
- ↑ "Nobel laureates challenge Indian astrophysicist's 'lumpy cosmos' claim". Nature India. 2013. doi:10.1038/nindia.2013.45.
- ↑ Abhas Mitra (28 August 2013). "Comments on the Essay 'Theoretical Physics: The Origin of Space and Time'". Nature (article comments).
- ↑ Abhas Mitra (6 August 2013). "Comments on the Nature Paper 'Spin Rate of Black Holes Pinned Down'". Nature (article comments).
- ↑ "Various Comments Made by Mitra in response to Nature News on Black Holes". Disqus.
- ↑ Abhas Mitra. "Eternally Collapsing Object". Eternal blogs on Wordpress.
- ↑ Abhas Mitra. "The Genesis of "Magnetospheric Eternally Collapsing Object"". Eternal blogs on Wordpress.
- ↑ "High Altitude Gamma Ray Observatory, Han Leh, India".
- ↑ "HBNI".
- ↑ "IAU".
- ↑ Mitra, Abhas (2018). "Mass of Schwarzschild Black Holes Is Indeed Zero And Black Hole Candidates Are Quasi Black Holes". arXiv:1708.07404.
- ↑ Mitra, Abhas (29 December 2010). "The fallacy of Oppenheimer Snyder collapse: no general relativistic collapse at all, no black hole, no physical singularity". Astrophysics and Space Science. 332 (1): 43–48. arXiv:1101.0601. Bibcode:2011Ap&SS.332...43M. doi:10.1007/s10509-010-0578-5.
- ↑ Mitra, Abhas (1 October 2002). "On the final state of spherical gravitational collapse". Foundations of Physics Letters. 15 (5): 439–471. arXiv:astro-ph/0207056. Bibcode:2002FoPhL..15..439M. doi:10.1023/A:1023968113757.
- ↑ Mitra, Abhas (10 July 2006). "Why gravitational contraction must be accompanied by emission of radiation in both Newtonian and Einstein gravity". Physical Review D. 74 (2). arXiv:gr-qc/0605066. Bibcode:2006PhRvD..74b4010M. doi:10.1103/physrevd.74.024010. Archived from the original on 4 November 2013.
- ↑ Mitra, Abhas (11 June 2006). "Radiation pressure supported stars in Einstein gravity: eternally collapsing objects". Monthly Notices of the Royal Astronomical Society. 369 (1): 492–496. arXiv:gr-qc/0603055. Bibcode:2006MNRAS.369..492M. doi:10.1111/j.1365-2966.2006.10332.x.
- ↑ Mitra, Abhas (November 2006). "Sources of stellar energy, Einstein Eddington timescale of gravitational contraction and eternally collapsing objects". New Astronomy. 12 (2): 146–160. arXiv:astro-ph/0608178. Bibcode:2006NewA...12..146M. doi:10.1016/j.newast.2006.08.001.
- ↑ Stanley L. Robertson and Darryl J. Leiter, Astrophysical J., 565 447 (2002) (Institute of Physics, UK)"Evidence for Intrinsic Magnetic Moments in Black Hole Candidates".
- ↑ "Particle creation by black holes" (PDF).
- ↑ "Big Bang: Indian physicist says he's vindicated".
- ↑ "Big Bang: Indian Physicist Abhas Mitra Feels Vindicated".
- ↑ "Indian physicist who opposed Big Bang origin says he's vindicated". Archived from the original on 22 December 2014.
- ↑ "Indian physicist claims he resolved Black Hole paradox much before Stephen Hawking".
- ↑ "This Indian physicist disproved black holes 13 years before Hawking".
- ↑ Mitra, A. (March 2010). "Einstein energy associated with the Friedmann-Robertson-Walker metric". General Relativity and Gravitation. 42 (3): 443–469. arXiv:0911.2340. Bibcode:2010GReGr..42..443M. doi:10.1007/s10714-009-0863-1.
- ↑ Mitra, A. (4 December 2012). "Interpretational conflicts between the static and non-static forms of the de Sitter metric". Scientific Reports. 2. Bibcode:2012NatSR...2E.923M. doi:10.1038/srep00923.
- ↑ Mitra, A.; Bhattacharyya, S.; Bhatt, N. (March 2013). "ΛCDM Cosmology Through the Lens of Einstein's Static Universe, the Mother of Λ". International Journal of Modern Physics D. 22 (3). Bibcode:2013IJMPD..2250012M. doi:10.1142/S0218271813500120.
- ↑ Mitra, A. (March 2013). "Energy of Einstein's static universe and its implications for the ΛCDM cosmology". Journal of Cosmology and Astroparticle Physics. 2013. Bibcode:2013JCAP...03..007M. doi:10.1088/1475-7516/2013/03/007.
- ↑ Mitra, A. (July 2014). "Why the Big Bang Model Does Not Allow Inflationary and Cyclic cosmologies Though Mathematically One Can Obtain Any Model With Favourable Assumptions". New Astronomy. 30: 46–50. Bibcode:2014NewA...30...46M. doi:10.1016/j.newast.2013.12.002.
- ↑ Mitra, A. (February 2014). "Testing R_h=ct Cosmology From Fundamental Considerations: Is the Friedmann Universe Intrinsically Flat". General Relativity And Gravitation. 46: 1–12. Bibcode:2014GReGr..46.1670M. doi:10.1007/s10714-014-1670-x.
- ↑ Mitra, A. (May 2011). "The matter in the Big-Bang model is dust and not any arbitrary perfect fluid!". Astrophysics & Space Science. 333 (1): 351–356. Bibcode:2011Ap&SS.333..351M. doi:10.1007/s10509-011-0635-8.
- ↑ "Physicist questions physical reality of 'Dark Energy'".
- ↑ "Black Hole Has Major Flare".
- ↑ "NASA capture calls for fresh look at black hole theories: Mitra".
- ↑ "Are Black Hole Ultra Hot Balls of Fire?". Archived from the original on 3 March 2016.
- ↑ "Black Holes Are Ultra Hot Balls Of Fire Like Our Sun: Scientist".
- ↑ "Exploring Magnetospheric Origin of Jets For Both Neutron Star and "Black Hole" Systems" (PDF).
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