Working on string theory using the methods from loop quantum gravity was a lot of fun.

On one of the few occasions when I talked to Richard Feynman, he said that many theoretical physicists spend their careers asking questions that are only of mathematical interest. “If you want to discover something significant,” he told me, “only work on questions whose answers will lead to new experimental predictions.”

The key thing that Amelino-Camelia and others realized is that we can use the universe itself as an experimental device to probe the Planck scale.

— Loop Quantum Gravity

— Lee Smolin

2010.12.14 Tuesday ACHK