'The papers themselves are perfectly respectable, undoubtedly correct, and interesting,' says cosmologist Sean Carroll of the California Institute of Technology. Wilczek describes his work in this article and in this one coauthored by Alfred Shapere of the University of Kentucky, that he posted on the physics preprint server,, on February 12. Such a crystal would represent a previously unknown state of matter and might have arisen as the very early universe cooled, losing its primordial symmetries.

He proposes that matter could form a 'time crystal,' whose structure would repeat periodically, as with an ordinary crystal, but in time rather than in space. But if Wilczek's latest ideas on symmetry and the nature of time are correct, they would suggest the existence of a bona fide perpetual-motion machine- albeit one from which energy could never be extracted. The phrases 'perpetual-motion machine'-a concept derided by scientists since the mid-19th century-and 'physics Nobel laureate Frank Wilczek' wouldn't seem to belong in the same sentence.

Diy perpetual motion machine