PCS 181- Final Exam Guide - Comprehensive Notes for the exam ( 41 pages long!)
30 Nov 2017
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Foundations: astronomy is the study of the universe, the totality of all of space, time, matter, and energy. It is a subject like no other - we need to change our perspectives of size, scales and times unfamiliar to us: the universe is huge so we must think big! Astronomers measure time in seconds & years: basic unit of time = second, time for earth to go around the sun = 1 year, = 365. 25 days = 3. 2x10^7 seconds, age of earth = 4. 6x10^9 years. Astronomers measure mass in kilograms: mass of astronomer, = 70 kilograms (kg, mass of earth, = 6x10^24kg, mass of sun, = 2x10^30kg, 330,000 x mass of earth. Asteroid = relatively small rocky object orbiting a star. Galaxy = a group of stars clumped together (by gravity) 100 billion stars in each: solar systems - planets, asteroids, comets revolving (orbiting) around one star, moons - revolving (orbiting) around planets.
