I never liked string theory. I never really understood it, so my reaction may simply be sour grapes. But this new theory of Loop Quantum Gravity promises to be a more elegant solution to unifying quantum mechanics to the Theory of Relativity. The even cooler thing is that the theory was created by 31-year old Markopoulou Kalamara, a woman in a field dominated by men. The article in Scientific American goes into excellent layman-level detail.
What I especially found intriguing was the concept of the observer. Usually, theories of the universe are presented in such a way that there is a definite "outside" for a hypothetical observer to observe from. This theory seems different in that the observed reality is the integrated view from the inside. This is similar to projection reconstruction in computed tomography or magnetic resonance imaging (my own field), in which multiple limited views are combined to reconstruct a full view:
Because the speed of light is finite, you can see only a limited slice of the universe. Your position in spacetime is unique, so your slice is slightly different from everyone else's. Although there is no external observer who has access to all the information out there, we can still construct a meaningful portrait of the universe based on the partial information we each receive. It's a beautiful thought: we each have our own universe. But there's a lot of overlap. "We mostly see the same thing," Markopoulou Kalamara explains, and that is why we see a smooth universe despite a quantized spacetime. "
Fascinating stuff, makes me wish I had enough knowledge to read the original paper. I'll look it up on ScienceDirect anyway and fantasize about being able to understand the formalisms. I really need to subscribe to SciAm though.
There also a Physics News Update on Loop Quantum Gravity at the American Institute of Physics, and a detailed technical overview culled from Google.
(the article was also posted to the UNMEDIA mailing list, and public archives)
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