ASTR 101 Lecture 1 Outline of Current Lecture I. The Essential Cosmic PerspectiveII. Our Place in the UniverseA. Define star, planet, moon, asteroid, galaxy and universe III. LightA. Destination and Light Travel TimeCurrent LectureThe Essential Cosmic Perspective- The mathematical perspective- The time and spaceAn Interesting URL: http://apod.nasa/gov- Bookmark and visit dailyChapter 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 galaxiesLight travels at a finite speed: 300,000 km/sDestination Light Travel TimeMoon 1 secSun 8 minSirius 8 yearsAndromeda Galaxy 25 million yearsThus, we see objects as they were in the past: the farther away we look the further back we look in
View Full Document
Unlocking...