No Hair, No Way: Understanding Black Holes
Black Holes have been one of the biggest stories in science since the start of the millenium. This is partly due to the discovery of solid evidence for a massive black hole near the center of our Milky Way galaxy, as well as the debate the past year over hazards at the giant French atom-smashing machine, the Large Hadron Collider [[LHC]].
Just to review, a black hole is a region in space where gravity is so strong nothing, not even light, can leave the region. There was speculation about such more than a century ago. The idea was put on a rigorous theoretical basis in Einstein's Genreal Theory of Relativity. Hard evidence for a massive black hole near the center of our Milky Way came from the Chandra X-Ray satellite observatory and the Very Long Baseline radio telescope array in the last half dozen years. It is now considered an effectively proven fact that we have a black hole weighing in at several million times our Sun's mass about 26 000 light years away, at the center of the Milky Way.
But theoretical understandking is dubious. Einstein's theory predicts a point of infinite mass density at the core of a black hole. This can hardly be verified because the interior of a black hole is unobservable.
And some theories regarding observable phonomena appear to this writer to be untenable. In particular, there is a theory called the "No Hair Theorem", which apparently started with the recently deceased physicist John Wheeler. This "theorem" states that a black hole has only three characteristics: Mass; charge; and spin [[or "angular momentum"]].
Black holes cannot possibly be that simple. First, we must define what is meant by "black hole". My understanding is that a black hole is whatever is inside the "event horizon" [["EH"]]. The event horizon is the invisible shell, outside of which, nothing can escape. This, as I understand it, is the usual definition.
A little thought shows that the EH cannot be a perfect sphere. Suppose a neutron star passes thru the EH. The gravitational field of the star will be added to the black hole. The size of the EH must expand.
But the EH cannot expand symmetrically at all points instantaneously. To do so would mean the "speed of gravity" [[or speed of gravitational waves]] inside the EH is infinite. No such theory has been postulated, as far as I can find, anywhere on the web. [[There is evidence that the black hole at or near the center of our Milky Way is ten to one hundred million miles in diameter. At the speed of light, it would take almost a minute for energy to cross such a Hole.]]
So a neutron star falling into a black hole would create a "bulge" in the EH around the point of the star's passage thru the EH, for at least some short time. The bulge would "spread" and flatten out, around the EH, as if a blob of water had been added to a ball of water floating in space. Or one might visualize it as a giant amoeba in space "swallowing" heavy objects and growing bigger around its bite.
And if spin is involved - and there is almost always spin involved - there seems to be no theory for the instantaneous transfer of momentum thoroughout the interior of a black hole. Somewhere I found a comment about a black hole being like a "superfluid". This would imply dramatic vortices are possible. A crude analogy of an infalling star then would be a block of ice falling into a Jacuzzi. The block would melt into the hot water and raise the overall level, but only after some churning, mixing, and wave action. Very much the same must clearly occur for heavy masses falling into black holes. Lighter masses, even dust, must have similar but smaller effects.
Even if total angular momentum for the "fluid" inside the EH could theoretically be represented with just one angular momentum vector, I would still question if there might not be some sort of externally observable phenomena related to all the possible radical internal conditions - the biggest questions arising from charge. Add electric charge to the [[possibly]] swirling, churnging, unabservable morass inside an EH and one must wonder what might be observed outside.
No "Hair"? No way.
-Harry Wertmuller
Just to review, a black hole is a region in space where gravity is so strong nothing, not even light, can leave the region. There was speculation about such more than a century ago. The idea was put on a rigorous theoretical basis in Einstein's Genreal Theory of Relativity. Hard evidence for a massive black hole near the center of our Milky Way came from the Chandra X-Ray satellite observatory and the Very Long Baseline radio telescope array in the last half dozen years. It is now considered an effectively proven fact that we have a black hole weighing in at several million times our Sun's mass about 26 000 light years away, at the center of the Milky Way.
But theoretical understandking is dubious. Einstein's theory predicts a point of infinite mass density at the core of a black hole. This can hardly be verified because the interior of a black hole is unobservable.
And some theories regarding observable phonomena appear to this writer to be untenable. In particular, there is a theory called the "No Hair Theorem", which apparently started with the recently deceased physicist John Wheeler. This "theorem" states that a black hole has only three characteristics: Mass; charge; and spin [[or "angular momentum"]].
Black holes cannot possibly be that simple. First, we must define what is meant by "black hole". My understanding is that a black hole is whatever is inside the "event horizon" [["EH"]]. The event horizon is the invisible shell, outside of which, nothing can escape. This, as I understand it, is the usual definition.
A little thought shows that the EH cannot be a perfect sphere. Suppose a neutron star passes thru the EH. The gravitational field of the star will be added to the black hole. The size of the EH must expand.
But the EH cannot expand symmetrically at all points instantaneously. To do so would mean the "speed of gravity" [[or speed of gravitational waves]] inside the EH is infinite. No such theory has been postulated, as far as I can find, anywhere on the web. [[There is evidence that the black hole at or near the center of our Milky Way is ten to one hundred million miles in diameter. At the speed of light, it would take almost a minute for energy to cross such a Hole.]]
So a neutron star falling into a black hole would create a "bulge" in the EH around the point of the star's passage thru the EH, for at least some short time. The bulge would "spread" and flatten out, around the EH, as if a blob of water had been added to a ball of water floating in space. Or one might visualize it as a giant amoeba in space "swallowing" heavy objects and growing bigger around its bite.
And if spin is involved - and there is almost always spin involved - there seems to be no theory for the instantaneous transfer of momentum thoroughout the interior of a black hole. Somewhere I found a comment about a black hole being like a "superfluid". This would imply dramatic vortices are possible. A crude analogy of an infalling star then would be a block of ice falling into a Jacuzzi. The block would melt into the hot water and raise the overall level, but only after some churning, mixing, and wave action. Very much the same must clearly occur for heavy masses falling into black holes. Lighter masses, even dust, must have similar but smaller effects.
Even if total angular momentum for the "fluid" inside the EH could theoretically be represented with just one angular momentum vector, I would still question if there might not be some sort of externally observable phenomena related to all the possible radical internal conditions - the biggest questions arising from charge. Add electric charge to the [[possibly]] swirling, churnging, unabservable morass inside an EH and one must wonder what might be observed outside.
No "Hair"? No way.
-Harry Wertmuller
posted by Harry Wertmuller at 1:26 PM
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