Unformatted text preview: of a perfectly circular orbit at the center of the epicycle.
a. A star in a perfectly circular orbit in the inertial frame would be seen to be
at rest at the “guiding center” in the frame rotating with the galaxy at the
same angular velocity as the star’s orbtial angular velocity in the inertial
frame. Gravity is clearly pulling the star toward the center of the galaxy,
even in the rotating frame. What force counters the pull of gravity to keep
the star at rest?
b. Why does a star, in the rotating frame, if perturbed outward from this
“guiding center,” orbit as an angular velocity that lags behind the “guiding
center”? Inversely, why does the star if pert...
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This document was uploaded on 03/04/2014 for the course ASTROPHYS 362 at Minnesota State University Moorhead .
- Spring '14