When a star moves away from earth, its electromagnetic spectrum stretches to make its wavelengths appear longer. which of these methods makes use of this phenomenon to measure accurately the distance from earth to a star? a. doppler effect b. parallax method c. hr diagram d. blue shift

Asatellite with an orbital period of exactly 24.0 h is always positioned over the same spot on earth. this is known as a geosynchronous orbit. television,communication, and weather satellites use geosynchronous orbits. at what distance would a satellite have to orbit earth in order to have a geosynchronous orbit?