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Doubting the Existence of Black Holes

The Good Reverend writes: "It seems that there's a growing movement that doubts the existence of black holes, going against most of the rest of astrophysics. They suggest the existence of gravastars, "star-size agglomerations of "wavelike" substance" (space-time fabric, if you will). Different scientists claim to have created the "wavelike substance" in a lab, called Bose-Einstein condensates." I understand gravastars taste terrific with cream cheese and red onion.

2 of 299 comments (clear)

  1. Schwarzschild radius by LMCBoy · · Score: 4, Insightful

    This "Gravastar" might be indistinguishable from a black hole. The article says that the star collapses to the point that the material undergoes some kind of phase transition to become a single waveform of space-time, analogous to a Bose-Einstein Condensate.

    If this happens when the object is less than a Schwarzschild radius in size, it would look and behave exactly like a black hole to an outside observer.

    (The Schwarzschild radius is the distance inside of which not even light can escape from the object. It doesn't make a difference how the matter is distributed inside the Schwarzschild radius)

    I'd also be interested to know how gravastars scale with mass. The article mentioned only stellar-mass black holes, but our greatest evidence for BHs is the supermassive black holes that are thought to exist at the centers of most massive galaxies. These have masses of millions of solar masses; can a gravastar hold up that much mass?

    --
    Liberal (adj.): Free from bigotry; open to progress; tolerant of others.
  2. Re:Perhaps someone could explain... by Mr_Dyqik · · Score: 5, Insightful

    I'm not talking about string theories which deal with 10d line objects, of which there are 5, but the parent theory of all 5 string theories and supersymmetry, that deals with membranes in 11-d.

    So far no one has produced any strong objections to m-theory, and m-theory has been used to produce a model (the Ekopyrotic model) for the instant of the big bang. The ramifications of this model are currently being worked out, by amoung others, Martin Rees, Steven Hawking and Neil Turok (in Cambridge alone). The current work is to calculate the effect the Ekopyrotic model has on nucleosynthesis, baryon fraction and primordial CMB imprints and structure formation in the early universe. With the advent of CMB anisotropy experiments such as the VSA, CBI, DASI, Planck and MAP, these predictions will be tested in the next decade or so.

    M-Theory also has possible implications for results in within the reach of the LHC accelerator at CERN, which should start producing results of searches for supersymmetric particles about a decade from now.

    QCD does have problems with renormalisation, and perturbation techniques at low energies, but these vanish as the energy of the particles increases.

    I won't comment on you theory above until you have a working mathematical model for the theory.