AS101 Study Guide - Midterm Guide: Tropical Year, Star Cluster, Declination
Document Summary
Everything we can possibly see is a tiny fraction. Massive ball of glowing gas that generates energy through nuclear fusion. Source of almost all energy on earth. Over 600 planets confirmed to be orbiting other stars. Thousands of candidate exoplanets, observed by the kepler space. Some planets have satellites (an object in orbit around a planet) Natural satellites are also known as moons . A small, rocky object orbiting a star. A small, icy object orbiting the sun. A large system of stars, dark matter, gas, and dust, all bound together by their combined gravity. Raw materials for new stars from previous generations. Our sun probably formed in an open star cluster but has since moved out . A group of galaxies (a few dozen up to thousands) all held together gravitationally. *there are more stars in the universe than grains of sand on all of the earth.
