Continuing with a cosmic theme, New Scientist has an article about loop quantum gravity that is guaranteed to make your head hurt.
First, of all, it would seem to be a workable theory:
For loop quantum gravity to succeed as a fundamental theory of gravity, it should at the very least predict that apples fall to Earth. In other words, Newton’s law of gravity should naturally arise from it. It is a tall order for a theory that generates space and time from scratch to describe what happens in the everyday world, but Carlo Rovelli at the University of the Mediterranean in Marseille, France, and his team have succeeded in doing just that. “Essentially we have calculated Newton’s law starting from a world with no space and no time,” he says (www.arxiv.org/abs/gr-qc/0604044).
Loop quantum gravity defines space-time as a network. The theory conceives of nodes in the network as infinitesimally small (10E-35) indivisible chunks of space. Theorists have focused upon how the links intertwine.
The origins of loop quantum gravity can be traced back to the 1980s, when Abhay Ashtekar, now at Pennsylvania State University in University Park, rewrote Einstein’s equations of general relativity in a quantum framework. Smolin and Carlo Rovelli of the University of the Mediterranean in Marseille, France, later developed Ashtekar’s ideas.
How does loop quantum gravity account for “dark matter”? And, if there is “dark matter” is there also “dark energy”?