Worldbook at NASA

Close up of a clear, uncoated quartz rotor reflecting a poster of Albert Einstein.

Relativity: Einstein's two theories are the "foundation blocks" of modern physics.

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The Gravity Probe B gyroscopes are the most perfect spheres ever made by humans. If these ping pong-sized balls of fused quartz and silicon were the size of the Earth, the elevation of the entire surface would vary by no more than 12 feet.

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Gravity Probe B Latest News

Related Links

    Stanford University
    A comprehensive information source on the Gravity Probe B experiment.
    > View site

    Gravity Probe B Launch
    Information about Gravity Probe B's 2004 launch from the Kennedy Space Center.
    > View site

Media Contacts

    Members of the media, please contact:

    Trent Perrotto, NASA Headquarters
    Washington, D.C.

    Robert Kahn, Stanford University
    Stanford, Calif.

    Janet Anderson, Marshall Space Flight Center
    Huntsville, Ala.