Space and astronomy news and information for the American Southwest. Coverage includes Vandenberg AFB rocket and missile launches.

Gravity Probe B Launched

by Brian Webb

2004 April 25

After years of delays, NASA’s Gravity Probe B has successfully reached orbit. A Delta II rocket left California's central coast Tuesday morning and inserted the $630 million satellite into an orbit that carries it over the poles. Preliminary information indicated that the orbit missed the poles by a mere 100 meters.

After a six-week checkout, the spacecraft will begin testing Einstein’s General Theory of Relativity, a profound concept published nearly a century ago. Einstein devised the theory to reconcile his earlier assertion that nothing can travel faster than the speed of light with Newtonian physics' contradictory view that the effects of gravity travel at unlimited speed. Among General Relativity's main points is the idea that the presence of gravity alters space and time.

For several decades the theory has served as the foundation of our understanding of space, time, and how the universe works on a grand scale. However, compared to other scientific theories, General Relativity has not been thoroughly tested.

Over the course of a year, scientists will measure how the spin of gyroscopes aboard Gravity Probe B change as the fabric of space-time is distorted by the Earth’s mass and twisted by its rotation.

Data returned by Gravity Probe B may verify General Relativity or utlimately lead to a new theory.

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Copyright © 2004, Brian Webb. All rights reserved.