Discover
/
Article

Frame dragging on flybys

MAR 01, 2010
Allen D. Allen

The Quick Study on Earth flyby anomalies (Physics Today, October 2009, page 76 ) teases the reader who is unfamiliar with the subject. We’re told of a microscopic, nonconserving change in the speed of a satellite as it flies by Earth. The slight change in kinetic energy may be increasing or decreasing, as if Earth’s rotation were being weakly added to the velocity of the satellite. Up to an altitude of 2000 km, an empirical fit of the data depends on a constant of proportionality equal to twice the product of Earth’s radius and angular velocity divided by the speed of light. What jumps immediately to mind is frame drag—the idea, according to general relativity, that spacetime in the vicinity of a rotating mass will be dragged around as the mass spins. Yet this point is absent from several proposed and seemingly far-fetched explanations. Even if frame drag fails quantitatively or in some omitted detail, it seems intuitive to the uninitiated and should have been addressed, given Physics Today’s diverse readership.

More about the Authors

Allen D. Allen. (aallen@cytodyn.com) Santa Fe, New Mexico, US .

Related content
/
Article
/
Article
/
Article
/
Article
This Content Appeared In
pt-cover_2010_03.jpeg

Volume 63, Number 3

Get PT in your inbox

pt_newsletter_card_blue.png
PT The Week in Physics

A collection of PT's content from the previous week delivered every Monday.

pt_newsletter_card_darkblue.png
PT New Issue Alert

Be notified about the new issue with links to highlights and the full TOC.

pt_newsletter_card_pink.png
PT Webinars & White Papers

The latest webinars, white papers and other informational resources.

By signing up you agree to allow AIP to send you email newsletters. You further agree to our privacy policy and terms of service.