Mark Semon

Mark Semon


Bates College


March 2, 2009

4:00 p.m.

Cardwell 102

Gravity Probe B and Thomas Precession


The satellite Gravity Probe B was launched in 2006 to measure three predictions of general relativity.  One of these predictions, Thomas Precession, is a purely kinematic effect that occurs whenever an object with spin moves in a closed orbit.  We present a simple derivation of Thomas Precession and use it to understand both the precession of gyroscopes on Gravity Probe B and the precession of the spin vector of an electron in a hydrogen atom.