Question for String Theorists?

Question

I recently saw the NOVA special on string theory. It left me pondering for the better part of the day. The program stated that there is a concentration of effort in using the atom-smashers to produce gravitons, in an attempt to document an "escaping" graviton which would provide proof of the theory. My question is if gravitons are detectable in the first place, wouldn't it be easier to find naturally occurring gravitons passing into or even through our brane, instead of trying to manufacture them? It seems to me that black holes would be better named "graviton stars," since according to what I understand of string theory, a graviton would be the only thing able to "escape" from the singularity. A black hole is, after all, a stellar sized atom smasher, so theoretically wouldn't they be radiating loads of gravitons? Even if all the gravitons are forced to exit our brane, wouldn't there be similar phenomena in parallel universes that would dump gravitons into our brane? Curious.

Answer 1

Gravitons were hypothesized long before string theory came along, arising from quantum field theory, which had already been successful in predicting the existence and behavior of other gauge bosons. String theory also predicts gravition (well, why not? string theory is actually an extension of quantum field theory), but also expands on its properites, including ability to "leak" between branes. However, they are difficult to detect, and one leading method is through detection of gravity waves, which large apparatuses have aleady been set up to do (LIGO project, e.g). A number of sources of gravitions naturally occurring in the universe have already been proposed and studied, such as synchrotron production by a massive binary system, for example. Attempts to detect them at the Large Hadron Collider at CERN is another example. Any way physicists can hope to detect gravitons, they're going to try. Now, you mentioned that gravitions are emitted from black holes, so why not try using the LHC to detect them? Surprise! That's been thought of too, and here's the link on that for you. Enjoy.

Answer 2

Well there is no proof that smashing an atom is the only way to produce gravitons. So simply having proof that gravitons exist is not enough. There has to be a documented case of an atom-smasher doing it.

But you probably shouldn't listen to me. I'm no physicist. :)

Answer 3

I believe your brane, would not be able to register the effects of gravity you need something to measure. The brain only observes the effects it is unable to register or measure in any form other than what is observable by the reality it perceives. The atom smasher is an instrument used to measure the effects of atoms movieng close to the speed of light. A black hole is not an atom smasher. It is a gravitational field. It in effect compresses matter into singulaity, something that goes beyond just smashing atoms, it is in effect a place where matter is recycled. A place where atoms are striped of their properties, and remade.