April 5, 2004

Interesting Physics Experiment

There is an article about a fascinating experiment in Wired Magazine: bq. A satellite designed to test two fundamental predictions made by Albert Einstein about the universe is ready for launch, 45 years after it was first proposed, NASA and Stanford University officials said. bq. Since 1959, Gravity Probe B has overcome a half-dozen attempts at cancellation, countless technical hurdles and several delayed launches. The NASA-funded, university-developed spacecraft is now scheduled to begin its mission following an April 17 liftoff from Vandenberg Air Force Base, Calif. And the experiment itself: bq. At the spacecraft's heart are four pingpong-sized balls of quartz, the most perfect spheres ever made. To ensure accuracy, the balls must be kept chilled to near absolute zero, in the vacuum of the largest thermos ever flown in space, and isolated from any disturbances in the quietest environment ever produced, Anne Kinney, director of the National Aeronautics and Space Administration's division of astronomy and physics, said Friday. And more: bq. If theory holds, the mass and rotation of the Earth, 397 miles below the probe, should throw the alignment of the spinning balls off kilter in subtle but measurable ways. bq. The warping effect has been measured before. The twisting effect, called frame-dragging, has never been directly detected. Gravity Probe B aims to detect both. Here is a website for the Satellite Here is a file (PDF) explaining the engineering in the gyroscope. Neat idea! Posted by DaveH at April 5, 2004 2:32 PM