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To: snarks_when_bored; RadioAstronomer; PatrickHenry
"We start with effects actually seen in the lab, which I think gives it more credibility than black holes," says Chapline. With this idea in mind, they - along with Emil Mottola at the Los Alamos National Laboratory in New Mexico, Pawel Mazur of the University of South Carolina in Columbia and colleagues - analysed the collapse of massive stars in a way that did not allow any violation of quantum mechanics. Sure enough, in place of black holes their analysis predicts a phase transition that creates a thin quantum critical shell. The size of this shell is determined by the star's mass and, crucially, does not contain a space-time singularity. Instead, the shell contains a vacuum, just like the energy-containing vacuum of free space.

It sounds to me that they're not actually *replacing* the idea of black holes with something else that's not a black hole, what they're really saying is that the physics of black holes might be different than previously thought, especially "inside" the black hole.

25 posted on 03/09/2006 10:38:13 PM PST by Ichneumon
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To: Ichneumon
It sounds to me that they're not actually *replacing* the idea of black holes with something else that's not a black hole, what they're really saying is that the physics of black holes might be different than previously thought, especially "inside" the black hole.

Well, as the passage you quoted states, at the heart of a black hole (should such there be) there's a spacetime singularity. That would not be the case for the Chapline dark energy star, inside of which there is vacuum but no singularity. Also, the event horizon of a black hole isn't made of any sort of 'stuff', while the quantum critical shell of a Chapline star would be. These are significant differences and would likely be enough to force a name change, don't you think?

27 posted on 03/09/2006 10:49:43 PM PST by snarks_when_bored
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To: Ichneumon; snarks_when_bored
It sounds to me that they're not actually *replacing* the idea of black holes with something else that's not a black hole, what they're really saying is that the physics of black holes might be different than previously thought, especially "inside" the black hole.

From what I read, the idea says that the thin shell of material forms just outside of where the event horizon would be. (This idea, which replaces black holes with objects called gravastars, was formulated by Mazur/Mottola some time around 2002.) If this phenomenon is true, it prevents a black hole from forming, but just barely. The surrounding space-time would still apparently behave just like a black hole outside the event horizon (but there would be stronger ejected matter jets & x-ray emission than in a standard black hole).

I have to honestly say that I don't understand how this would solve the dark matter problem any more than saying it is tucked away into black holes, though. (Primordial black holes would have to evaporate into observable photons by Hawking radiation, whereas these entities don't, I'm guessing...)

Some older links on the matter:

Los Alamos researcher says 'black holes' aren't holes at all

Thick-Skinned Gravastars Vie to Replace Black Holes, in Theory

Is black hole theory full of hot air? (Typically misleading title courtesy of CNN)

Great article, snarks - always fun to discuss true controversies in science.

46 posted on 03/10/2006 7:14:20 AM PST by Quark2005 (Confidence follows from consilience.)
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To: Ichneumon; snarks_when_bored; Physicist; Quark2005
It sounds to me that they're not actually *replacing* the idea of black holes with something else that's not a black hole, what they're really saying is that the physics of black holes might be different than previously thought, especially "inside" the black hole.

The article says:

The team's calculations show that the vacuum energy inside the shell has a powerful anti-gravity effect, just like the dark energy that appears to be causing the expansion of the universe to accelerate. Chapline has dubbed the objects produced this way "dark energy stars".

Though this anti-gravity effect might be expected to blow the star's shell apart, calculations by Francisco Lobo of the University of Lisbon in Portugal have shown that stable dark energy stars can exist for a number of different models of vacuum energy. What's more, these stable stars would have shells that lie near the region where a black hole's event horizon would form ...

Presumably (I'm operating with very little info) this anti-gravity effect would prevent the singularity which is supposed to be at the center of black holes. Otherwise, they'd be similar objects, except for the subtle effects at the horizon, which might be observable.
58 posted on 03/10/2006 8:34:24 AM PST by PatrickHenry (Virtual Ignore for trolls, lunatics, dotards, scolds, & incurable ignoramuses.)
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