Astronomy Chapter 26 Studying Space

Astronomy  The scientific study of the universe Benefits  Exciting discoveries Black holesBlack holes pulsarspulsars new planetsnew planets nebulasnebulas  Protection  New energy sources

Cosmology  The study of the origin, properties, processes and evolution of the universe  Big bang-- universe is about 14 billion years old ExpandingExpanding  Tools used are telescopes and math

Organization  Clusters of galaxies  Our galaxy is the Milky Way galaxy  Galaxy —a large collection of stars, dust and other objects like asteroids and comets  Our solar system is a tiny part in one spiral arm of the galaxy

Measuring distance  Distance is measured with the AU astronomical unit 1 AU = the average distance between the Earth and sun1 AU = the average distance between the Earth and sun  Another unit used is the light year A light year is the distance that light travels in one yearA light year is the distance that light travels in one year

Observing Space  We usually think of studying the light from stars  Visible light is a small part of the electromagnetic spectrum

Electromagnetic spectrum  Radio  microwave  Infrared  Visible light  Ultraviolet  X-rays  Gamma rays

Electromagnetic spectrum

telescopes Optical telescopes  Refracting telescopes Bending of light by lensesBending of light by lenses MagnifiesMagnifies  Reflecting telescopes Uses curved mirrorsUses curved mirrors Can be much largerCan be much larger Keck Telescopes in HawaiiKeck Telescopes in Hawaii

Telescopes for invisible radiation  Radio  Gamma rays  X rays  infrared

Space-based astronomy  Hubble space telescope  Spacecraft  Visit planets Voyager I and II—Voyager I and II— GalileoGalileo Cassini-HuygensCassini-Huygens

Human Space Exploration  people went to the moon12 people went to the moon  Space shuttles 2 lost2 lost