- Magnetospheric eternally collapsing object
Magnetospheric Eternally Collapsing Objects or MECOs are proposed alternatives to black holes advocated by Darryl Leiter and Stanley Robertson. They are a variant of eternally collapsing objects or ECOs proposed by Abhas Mitra in 1998. Mitra had devised an ostensive proof that black holes cannot form from the spherically symmetric gravitational collapse of a star. Based on this, he argued that the collapse must be slowed to a near halt by radiation pressure. A proposed observable difference between MECOs and black holes is that the MECO can produce its own magnetic field. An uncharged black hole cannot produce its own magnetic field, but its accretion disc can. Astronomer Rudolph Schild claims to have found evidence of such a magnetic field from the black hole candidate in the quasar Q0957+561.
Neither ECOs nor MECOs have gained any significant acceptance among scientists; Gerry Gilmore of the Institute for Astronomy at the University of Cambridge has stated that the concept is "almost certainly wrong," and the mathematician Chris Hillman has stated that it is "flat out wrong". Mitra's proof that black holes cannot form is based on the argument that in order for a black hole to form, the collapsing matter must travel faster than the speed of light with respect to a fixed observer. Paulo Crawford and Ismael Tereno have cited this as an example of a "wrong and widespread view," and explain that in order for a frame of reference to be valid, the observer must be moving along a timelike worldline. At or inside the event horizon of a black hole, it is not possible for such an observer to remain fixed; all observers are drawn toward the black hole.
- ^ D. Leiter, S. Robertson (2003). "Does the Principle of Equivalence Prevent Trapped Surfaces From being Formed in the General Relativistic Collapse Process?". Foundations of Physics Letters 16 (2): 143. arXiv:astro-ph/0111421. doi:10.1023/A:1024170711427.
- ^ A. Mitra (1998). "Final State of Spherical Gravitational Collapse and Likely Sources of Gamma Ray Bursts". arXiv:astro-ph/9803014 [astro-ph].
- ^ R.E. Schild, D.J. Leiter, S.L. Robertson (2006). "Observations Supporting the Existence of an Intrinsic Magnetic Moment inside the Central Compact Object within the Quasar Q0957+561". Astronomical Journal 132 (1): 420–432. arXiv:astro-ph/0505518. Bibcode 2006AJ....132..420S. doi:10.1086/504898.
- ^ I. Sample (30 July 2006). "US team's quasar probe sinks black hole theory". The Age.com. http://www.theage.com.au/news/world/us-teams-quasar-probe-sinks-black-hole-theory/2006/07/29/1153816426971.html.
- ^ C. Hillman, J. Baez (17 August 2004). "Indian physicist vindicated in black hole controversy: Reply by John Baez". sci.physics.relativity. http://groups.google.com/group/sci.physics.relativity/msg/4aafdaf243ae90aa?.
- ^ A. Mitra (2000). "Non-occurrence of Trapped Surfaces and Black Holes in Spherical Gravitational Collapse: An Abridged Version". Foundations of Physics Letters 13 (6): 543. arXiv:astro-ph/9910408. doi:10.1023/A:1007810414531.
- ^ P. Crawford, I. Terano (2002). "Generalized observers and velocity measurements in General Relativity". General Relativity and Gravitation 34 (12): 2075–2088. arXiv:gr-qc/0111073. doi:10.1023/A:1021131401034.
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