ASTR 205 Astronomy Chapters 1, 2, and 3

A solar system contains - the sun and the non luminous objects that orbit it, including the planets, comets, and asteroids field of view - the region you can see in an image planet - non luminous object, larger than a comet or asteroid, that orbits a star star - celestial object composed of gas held together by its own gravity and supported by nuclear fusion occurring in its interior AU - astronomical unit that is the average distance from the Earth to the sun light year - distance light can travel in one year. Nearest star is 4.2 ly from the sun galaxy - contains many billions of stars spiral arm - long, spiral pattern of bright stars that extends from the center to the edge of the disk of spiral galaxies moon is only ____ diameter of earth - 1/4 sun is ___ times larger in diameter than earth - 100 big bang - happened 14 billion years ago, and filled the universe with hot gas stars shined ___ million years after the big bang - 400 sun and planets formed ___ billion years ago - 4.6 How many centimeters are there in one kilometer - 100,000 Counts everything after the decimal, including non zeros - Scientific notation 64,200,000,000 is equal to - 6.42 X 10^10 If light takes 8 minutes to reach Earth from the sun and 5.3 hours to reach Pluto, what is the approximate distance from the sun to Pluto? - 40 AU The sun is - a star; 1 AU from Earth; more than 100 times the diameter of Earth If the nearest star is 4.2 light-years away, then - the light we see left the star 4.2 years ago Which arrangement is in order of increasing size, left to right - planet, star, solar system, galaxy