Aphelion and Perihelion

Aphelion is the greatest distance between a planet or other body and the Sun. Perihelion is the closest distance from the Sun. Objects move slowest in their orbits when they are aphelion and fastest when at perihelion.

Radio Programs

Moon and Antares A journey to a stellar supergiant Friday, March 21, 2014
Getting Close Snuggling close to two giants Friday, January 3, 2014


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