AST 2002 Lecture Notes - Lecture 2: Milky Way, Galaxy, Ytterbium
Document Summary
Universe made the carbon, the calcium, and the oxygen necessary to construct complex humans: tracing the evolution of man and the universe is one of the most important parts of modern astronomy. When ancient astronomers created models that earth was the center of the universe and everything moved around it in circular orbits. That huge chunks of rock and ice that hit earth have for like on earth itself is still debated: another ex. If contradicted the scientist must try to develop an alternative. 1. 4 numbers in astronomy: adopt two approaches for dealing with astronomical numbers, scientific notations (aka powers-of-ten notation, good b/c it eliminates the many zeros. 500,000,000 is 5 x 10^8: second way is to use a consistent set of units- the metric international system of. Light travels 3 105 k(cid:373) i(cid:374) (cid:1005) s. so, let"s calculate ho(cid:449) far it goes i(cid:374) a year: Thus, light covers 3 105 km/s 3. 6 103 s/h = 1. 08 109 km/h.
