AST 111 Lecture Notes - Lecture 1: Angular Distance, Constellation, Angular Diameter

• School: Tunxis Community College
• Department: Astronomy
• Course: AST 111
• Professor: Reynolds

Document Summary

Astronomical unit (au): earth"s average distance from the sun, about 150 million km or 90 million miles, commonly describe distances within our solar system with this. Light year: distance that light can travel within one year, about 10 trillion km or 6 trillion miles, using light years to describe distances of stars and galaxies. The farther away we look into the distance, the farther back we are looking in time. Age of the universe is 14 billion years, meaning we cannot see beyond 14 billion light years. Observable universe: the portion of the entire universe that we can potentially observe. Rotation: the earth spinning on its axis; rotates once each day in a counter clockwise direction. Orbit: the earth making revolutions around the sun; makes one full revolution in one year, in a counter clockwise direction. Ecliptic plane: the path the earth"s orbit makes around the sun.