Einstein's Cosmic Speed Limit Passes New Test

by Clara Moskowitz, Assistant Managing Editor   |   July 31, 2013 10:56am ET

Now and then, Einstein deserves to be tested. To that end, scientists have put his special theory of relativity — particularly its notion of the speed of light as the cosmic speed limit — to the test.

Physicists measured the energy required to change the speed of electrons as they hopped from one orbital to another inside atoms of dysprosium, all while Earth rotated over a 12-hour period.  [Read more] ...