ASTR 1101 : Astronomy 1101 Midterm Review
Document Summary
Geocentric model= an earth centered theory of the universe. Heliocentric model= a sun-centered theory of the universe. Gravitational force= force with which all matter attracts all other matter. Parallax= apparent displacement of an object due to motion of observer. Retrograde motion= apparent westward motion of a planet with respect to background stars. Right ascension= coordinate for measuring east-west positions of objects on celestial sphere. Declination= angular distance of celestial object north or south of celestial equator. Celestial equator= great circle on celestial sphere 90 degrees from celestial poles. North celestial pole= point directly above earth"s north pole where earth"s axis of rotation, if extended, would intersect celestial sphere. South celestial pole= point directly above earths axis of rotation, if extended, would intersect celestial sphere. Ecliptic= apparent annual path of sun on celestial sphere. Circumpolar stars= star that neither rises nor sets but appears to rotate around one of celestial poles.
