AST 111 Exam 1 || Already Passed.

A lightyear is the distance that _________ can travel in one _____ correct answers light, year How many km in a lightyear? correct answers 9.50 x 10^12 km How many KM in an AU correct answers 1.5 x 10^8 How many AU in a lightyear correct answers 63,000 AU Earth is a planet while the Sun is a________ correct answers Star Solar System correct answers consists of the sun, the planets, and some smaller bodies such as moon, asteroids, and comets - one planetary system Name the planets of the Solar System from closest to farthest from the Sun. correct answers Mercury, Venus, Earth (inner planets), Mars, Jupiter, Saturn, Uranus, Neptune Dwarf Planet correct answers An object that orbits the sun and is spherical, but has not cleared the area of its orbit. ex. Pluto extrasolar planets correct answers planets orbiting stars other than our Sun - very small galaxy correct answers a great cloud of stars, gas, and dust held together by the combined gravity of its matter. 1000ly to more than 300,000 ly in diameter. Contains billions of solar systems What galaxy do we live in? correct answers Milky Way Galaxy universe correct answers Includes all the galaxies, stars, planets, and other bodies that they may contain. Clusters - voids and walls correct answers Clusters of galaxies are grouped into superclusters and those are linked to form long filaments and walls outlining nearly empty voids. This walls appear to to be the largest structures in the universe how do astronomers detect extrasolar planets? correct answers They must be detected indirectly because they are too faint and too close to their parent stars for accurate imaging. As a planet orbits a star, gravitationally pulling the star first one way and then the other, the star "wobbles" slightly. The star will "wobble" more if the planet is more massive or if the sun is less massive. If an observer notices these wobbles, he/she is able to measure these gravitational fluctuations which allow us to estimate the extrasolar planet's mass. How old is the universe? correct answers 14 billion years old