Wednesday, July 16, 2008

Entropy and Hawking Radiation.

As I get older, I increasingly "get" the fact that I DON'T "get it". Nothing brings this more home to me than the dissipation of energy from Black Holes, or what is known now as Hawking Radiation. Named for the conjecture made in the 1970's by the "theoretical physicist", Stephen Hawking (Cambridge).

What concerns me here is the Black Holes themselves; they appear to be entirely too significant. Virtually every thing we see in space is oriented around these huge sucking places. Black Holes are gobbling everything up. Where they go, there goes the universe, literally, and nothing "theoretical" about this Physics.

How can galaxies--ALL of them--ever, or in the spitting instant of the Big Bang, or in an eternity, ever be "built" around places that gobble up stuff?

It gets worse. This concept of "evaporation", or the escape of heat, from the Black Hole horizon. As an object descends, orbits, into the Black Hole, it clearly reaches a point, the invisible "horizon" from which there is no return. From the descending object, the other stars will appear frozen.

There may be a similar "horizon" of time and light as a result of the accelerating expansion of the universe. The light from the most distant galaxies will be receding at light speed, and will not reach us. The distant objects will appear "frozen".

And worse. A central principle of Physics, and certainly quantum mechanics, is that energy is conserved. The information does not just "evaporate" or radiate off to become lost in some way like steam from a boiling pot of water. Within the collapse of an dense Black Hole, there is heat that is getting shredded and scrambled, but it is not "lost". The information falling into the Hole must exist, perhaps as a coating of the Black Hole's horizon.

What is the peculiar nature of the singularity at the small revenant center of a Black Hole? Is the principle of conservation of energy operating here? Or is Entropy itself destroyed in the infinitely dense. At that point, in the center of the Black Hole, as stuff collapses to a point, the concepts of large and small, heavy or light, macro and quantum, old and new, are all transformed.

I just cannot "get it". The foundations of our Physics are apparently at stake, right? Everything getting older, colder, darker, slower, and collapsing into Black Holes -- now that makes perfect sense, but then this What? These things "radiate"? We need more than Susskind's 10-dimensional strings projected in holographic horizons to cobble our universe together.

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