Chapter 1 COSMOLOGY- the study of the overall structure and history of the Universe, and a different picture has emerged. Over the centuries, two schools of thought developed concerning how to explain the configuration of stars and planets and their relationships to the earth, sun and moon. -The First class- advocated a GEOCENTRIC MODEL- in which the Earth sits motionless at the center of the Universe while the moon and the planets whirl around it, and everything lies inside a revolving globe of stars. -The Second class- advocated a HELIOCENTRIC MODEL- in which the sun lies at the center of the Universe while the earth and other planets orbit around it. The UNIVERSE is all of space and the matter and energy within it. STARS- is actually an immense ball of plasma (incandescent gas) that emits intense heat and light. Stars are not randomly scattered through the Universe. Rather, gravity holds them together in immense groups called GALAXIES. Our sun, together with 300 billion other stars, makeup the MILKY WAY GALAXY.
- Spring '17
- Solar System, Planet