Friday, September 24th, 2010

Testing Relativity With Better Clocks

NIST postdoctoral researcher James Chin-wen Chou with an ultra-precise clock based on the vibrations of a single aluminum ion. The ion is trapped inside the metal cylinder at center right. Credit: J. Burrus/NIST.

With a precise enough clock, it's possible to test the time-dilation effects predicted by Einstein's theory of relativity -- without a space ship. Writing this week in the journal Science, researchers at NIST describe their experiments using two highly-precise aluminum ion atomic clocks, linked by an optical fiber. Due to the precision of the clocks, they were able to observe differences in the passage of time over a height difference of just 33 centimeters, or at speeds as low as 20 miles per hour. We'll talk about the work and what it shows.