Gravity Probe B: Difference between revisions

Revision as of 19:13, 17 October 2005

Revision as of 22:54, 20 October 2005

Line 17:

The ''Gravity Probe B'' experiment comprises four gyroscopes and a reference [[telescope]] sighted on HR8703 (also known as [[IM Pegasi]] [http://simbad.u-strasbg.fr/sim-id.pl?protocol=html&Ident=HR+8703]), a [[binary star]] in the constellation [[Pegasus (constellation)|Pegasus]]. In [[polar orbit]], with the gyro spin directions also pointing toward HR8703, the frame-dragging and geodetic effects come out at right angles, each gyroscope measuring both.

[[Image:Einstein gyro gravity probe b.jpg|thumb|350px|right|One of the most perfect [[sphere]]s ever created by humans. A [[fused quartz]] [[gyroscope]] for the [[Gravity Probe B]] experiment which differs from a perfect sphere by no more than a mere 40 atoms of thickness as it [[refraction|refracts]] the image of Einstein in background. It is thought that only [[neutron star]]s are smoother.]]

The gyroscopes are the most spherical objects ever made. Approximately the size of ping pong balls, they are perfectly round to within forty atoms. They are composed of [[fused quartz]] and coated with [[niobium]]. The gyros' spin axes are sensed with [[SQUID]]s.