February 2008 Meeting Summary

On February 9, 2008, the Southern California Chapter of the ION held a meeting, hosted by NavCom in Torrance, CA. The meeting included a presentation from Gaylord Green, Director of the Gravity Probe B program at Stanford. A short biography and abstract of the meeting follows.

Brief Resume of Gaylord Green 
Col Gaylord Green (Ret) is a former director of the GPS program and was in the original program office cadre when the program was initiated in charge of the space segment. Additionally, Gaylord directed the guidance shop for the Minuteman/Peacekeeper inertial guidance systems. Since retiring from the Air Force, he is exploring space-time with the world’s most accurate gyroscope in NASA’s Gravity Probe B program.

Abstract of Colonel Gaylord Green’s Talk
Gravity Probe B (GP-B) is a physics mission to experimentally investigate Albert Einstein’s 1916 general theory of relativity. GB-B uses four spherical gyroscopes and a telescope, housed in a satellite orbiting 642 km (400 mi) above the Earth, to measure in a new way, and with unprecedented accuracy, two extraordinary effects predicted by the general theory of relativity:

  1. The geodetic effect—the amount by which the Earth warps the local space-time in which it resides.
  2. The frame-dragging effect—the amount by which the rotating Earth drags its local space-time around with it.

The GP-B experiment tests these two effects by precisely measuring the precession (displacement) angles of the spin axes of the four gyros over the course of a year and comparing these experimental results with predictions from Einstein’s theory.