

Black Holes and Speed of Light
Name: Thomas
Status: student
Age: N/A
Location: N/A
Country: N/A
Date: N/A
Question:
Yesterday, I was at the Stephen Hawking lecture at Cal Tech. He
described Einstein's Black hole as a very large "dent" in spacetime
created by super dense and heavy objects. He gave the example of a rubber
sheet and something like a lead ball. The ball will create a "black hole"
in the rubber sheet. The objects will fall into the dent and this is
Einstein's gravity. If this is gravity than density and weight would not
effect the size of the dent and only the mass or size of the object would
effect the gravity. Stephen Hawking described that using the uncertainty
principle that light can go faster than 186,000 miles per second and can
therefor escape from the Black hole. How does this redefine the theory of
relativity? (2008)
Replies:
In a sense yes. The classical theory of relativity assumes classical
mechanics. What Hawking did was to apply the Heisenberg Uncertainty
Principle to black holes. The Uncertainty Principle is a quantum mechanical
concept. At a sufficiently small scale there is not ever an infinite sharp
boundary, there is always a small but nonzero probability that a particle,
even light, can "tunnel" through a finite barrier. Far be it for me to
contest Hawking's interpretation, but regardless of how you want interpret
the phenomenon, black holes can "leak".
Vince Calder
Thomas,
It does not redefine relativity. This is the place where neither
quantum physics nor relativity applies correctly: a large, very dense
bundle of matter. When things are very small (an electron or an atom)
and not TOO fast, quantum physics works well. When things are far apart
and very fast, relativity works well. When things are not too small and
not too fast, Newtonian physics works well. Isaac Newton's theories are
an average effect of quantum physics and a smallspeed approximation of
relativity. When you get to situations like black holes, things are too
massive and too fast for quantum physics. Things are too close together
for relativity. This is why string theory is being developed. Quantum
physics works well with electromagnetic force and atomic forces.
Relativity works well with gravity. String theory is an attempt to find
the link between relativity and quantum physics, to find a theory that
applies in all cases. Neither quantum physics nor relativity is
perfect.
Dr. Ken Mellendorf
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Update: June 2012

