Introduction (Astronomy)

Recall cards introducing astronomy. What astronomy studies and where the elements of life were made. The nature of science: hypotheses, observational versus historical science, and peer review. The universality of physical laws. Numbers in astronomy: scientific notation, the speed of light, and the light-year. Light travel time and looking back in time. A tour of the solar system: planets, stars, the astronomical unit, and the sizes and distances of the Earth, Moon, and Sun. The Milky Way and the large-scale universe: galaxies, constellations, the Local Group, Andromeda, superclusters, and quasars. The universe of the very small: atoms, molecules, elements, and the density of matter in air, interstellar, and intergalactic space. Carl Sagan's cosmic calendar.