(Greek: star, stars, star shaped; also pertaining to outer space)
2. A unit of length used by astronomers to measure distances in space.
One astronomical unit, or AU, is equal to the average distance between the earth and the sun, which is 92,955,806 miles or 149,597,870 kilometers.
2. Referring to anything which is large in size or quantity: "The cost of health care has risen astronomically."
Astronomy literally means "law of the stars" or "culture of the stars"; depending on the translation, and it is derived from the Greek αστρονομία, astronomia, from the words άστρον, astron, "star" and νόμος, nomos, "laws" or "cultures".2. The science that deals with the material universe beyond the earth's atmosphere.
3. The scientific study of the universe, especially of the motions, positions, sizes, composition, and behavior of astronomical objects.
These objects are studied and interpreted from the radiation they emit and from data gathered by interplanetary probes.
2. The photography of stars and other celestial objects.
3. The use of photographs to record extraterrestrial objects in order to study their surface features, positions, motions, radiation, and spectra.
2. The measurement of the intensity of light of celestial objects.