ASTR 101 Lecture 1 Outline of Current Lecture I The Essential Cosmic Perspective II Our Place in the Universe A Define star planet moon asteroid galaxy and universe III Light A Destination and Light Travel Time Current Lecture The Essential Cosmic Perspective The mathematical perspective The time and space An Interesting URL http apod nasa gov Bookmark and visit daily Chapter 1 Our Place in the Universe Star large glowing ball of gas that generates heat and light through nuclear fission Planet moderately large object that orbits a star it shines by reflected light Planets may be icy rocky or gaseous Moon an object or rock that orbits a planet Asteroid a relatively small and rock object that orbits a star Galaxy great island of stars in space all held together by gravity and orbiting a common center Universe the sum total of all matter and energy everything within and between all galaxies Light travels at a finite speed 300 000 km s Destination Moon Sun Sirius Andromeda Galaxy Light Travel Time 1 sec 8 min 8 years 25 million years Thus we see objects as they were in the past the farther away we look the further back we look in time
View Full Document
Unlocking...