AST 2002 Lecture Notes - Lecture 1: Cosmic Calendar, Azimuth, Angular Distance
Document Summary
Our cosmic address: 1 one 10^0, 1000 thousand kilo 10^3, 1000000 million mega 10^6, 1000000000 billion giga 10^9, 1000000000000 trillion tera 10^12. A light year- the distance light can travel in 1 year= 10 trillion kilometers, 6 trillion miles. An astronomical unit average distance from earth to the sun= 1. 5 million kilometers. Planet- moderately large object that orbits the star: orbit a star, large enough to be round, has cleared most other objects from its orbit. The international astronomical union does not classify pluto as a planet because it has not cleared its orbital neighborhood of other objects. Moon- object that orbits a planet (ex: ganymede- orbits jupiter), saturn- 64 moons. Asteroid- relatively small and rocky object that orbits a star. Comet- relatively small and icy object that orbits a star. Solar (star) system- star and all the material that orbits it, including its planets and moons. Nebula- interstellar cloud of gas and/or dust.
