AS101 Chapter : AS101 Textbook notes
Document Summary
Chapter 1 the scale of the cosmos: space and time. 1. 1 from solar system to galaxy to universe. Astronomical unit average distance from earth to the sun; 1. 5x108 km. Solar system consists of the sun, its family of planets, and some smaller bodies, such as moons, asteroids, and comets. Planet a non-luminous body in orbit around a star, large enough to be spherical and to have cleared its orbital zone of other objects: they shine by reflecting sunlight. Sun is about 110 times larger in diameter than earth. Light from the sun reaches earth in only 8 minutes. Sun is a fairly typical star, a bit larger than average, and located in a fairly normal neighbourhood in the universe. Light year (ly) unit of distance equal to the distance light travels in one year, roughly 1013km or. Nearest star to the sun is proxima centauri which is 4. 2ly from earth.
