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Gravity Probe B

Testing Einstein's Universe

SPACETIME: From the Greeks to Gravity Probe B

Before Einstein

Before Einstein

Who first conceived of space and time, apart from matter? What did Greek and other philosophers have to say? How about Newton? What does Mach's principle really mean? Can it be tested?

Go to Spacetime Before Einstein.

Einstein's Spacetime

Einstein's Spacetime

How did Einstein change our views of space and time? Who else played a part? Did Einstein base his theory on Mach's principle? Does spacetime exist absolutely in general relativity? Is it "more relative" than in special relativity?

Go to Einstein's Spacetime.

Testing Einstein

Testing Einstein

Why is it more important to test Einstein's theory of general relativity now than ever before? What aspects of the theory have been tested so far, and to what accuracy? What remains to be done?

Go to Testing Einstein.

Spacetime & Spin

Spacetime & Spin

How does spacetime affect spinning bodies, and vice versa? Are there analogies between gravity and electromagnetism? What are the geodetic and frame-dragging effects? What will the results of the GP-B experiment tell us about fundamental physics, black holes, and the origin of inertia?

Go to Spacetime & Spin.

Further Reading

Further Reading

A collection of useful books, magazine and journal articles, and online resources for those who want to learn more about relativity and spacetime.

Go to Spacetime—Further Reading.

Relativity Q&A

Relativity Q&A

A collection of informative questions and answers compiled by Sten Odenwald. Courtesy of NASA's "Ask the Space Scientist" Web site.

Go to Relativity Q & A.