ASTR-1010 Lecture Notes - Lecture 1: Milky Way, Galactic Center, Observable Universe

• School: Clemson University
• Department: Astronomy
• Course: ASTR-1010
• Professor: Lih- Sin The

Document Summary

Earth is the third planet in the solar system, solar system is halfway from galactic center. Star large ball of gas, the center of a star is so hot that there is a nuclear reaction that creates heat and light. Planet an object that orbits a star - can be rocky, icy or gaseous can be seen because it reflects light. Moon (or satellite) - rocky object that orbits a planet. Asteroid relatively small and rocky, orbits a star, very elliptical orbit. Comet small and icy object that orbits a star. Solar system the sun and all the material that orbits it. Star system star and all the material that orbits it. Nebula cloud of gas and/or dust, where a star is born. Galaxy collection of stars held together by gravity. Cluster of galaxies galaxies bound by gravity. Small collections (100) are groups while larger collections (1,000) are clusters. Super cluster many groups and clusters of galaxies packed closely together.