[b]Lee Smolin
So, in the end, the most improbable and hence the most puzzling aspect of space is its very existence. The simple fact that we live in an apparently smooth and regular three dimensional world represents one of the greatest challenges to the developing quantum theory of gravity. If you look around at the world seekimg mystery, you may reflect that one of the biggest mysteries is that we live in a world in which it is possible to look around, and see as far as we like. The great triumph of the quantum theory of gravity may be that it will explain to us why this is so.[/b]
He means RM/AO of course.
I have already mentioned two features that successful unifications tend to share. The first, surprise, cannot be underestimated. If there is no surprise, then the idea is either uninteresting or something we knew before. Second, the consequences must be dramatic: The unification must lead quickly to new insights and hypothesis, becoming the engine that drives progress in understanding. But there is a third factor that trumps both of these. A good unified theory must offer predictions that no one would have thought to make before. It may even suggest new kinds of experiments that make sense only in light of the new theory. Most important of all, the predictions must be confirmed by experiment. These three criteria-surprise, new insights, and new predictions confirmed by experiment-are what we will be looking for when we come to judge the promise of current efforts at unification.
He means VO of course.
In fact, the particle-antiparticle annihilation and the closing of the string is necessary, if the theory is to be consistent with relativity, meaning the theory is required to have both open and closed strings. But this means it must include gravity. And the difference between gravity and the other forces is naturally explained, in terms of the difference between open and closed strings. For the first time, gravity plays a central role in the unification of the forces.
Give the cat some string and test it.
Extending Polyakov’s argument, he found evidence that the string theory describing those emergent strings is actually a ten-dimensional supersymmetric string theory. Of the nine dimensions of space in which these strings live, four of them are like the ones in Polyakov’s conjecture. There are, then, five dimensions left over, which are extra dimensions as described by Kaluza and Klein. The extra five dimensions are arranged as a sphere. The four dimensions of Polyakov are curved, too, but in the opposite way from a sphere; such spaces are sometimes called saddle-shaped. These correspond to universes with dark energy, but where the dark energy is negative.
Anyone here know if this has actually been demonstrated? You know, so that “all rational men and women are obligated to believe it.”
Whatever is happening on very small scales near the horizon of the black hole will be enlarged by the effect whereby the wavelengths of light are stretched as the light climbs up to us. This means that jf we can observe light coming from very close to the horizon of a black hole, we may be able to see the quantum structure of space itself.
Don’t try this at home.
When someone answers a question about the foundations of a subject, it can change everything we know.
You all know my three.