Confirming Einstein, scientists find 'spacetime foam'

One hundred years after Albert Einstein formulated the general theory of relativity, an international team has proposed another experimental proof. In a paper published today in Nature Physics, researchers from the Hebrew University of Jerusalem, the Open University of Israel, Sapienza University of Rome, and University of Montpellier in France, describe a proof for one of the theory's basic assumptions: the idea that all light particles, or photons, propagate at exactly the same speed.