Chapter 16 Learning Objectives

After reading, studying, and discussing the chapter, students should be able to:
 

·        Understand the Big Bang theory of the origin of the universe.

Chapter 16 Outline

I.  Red shifts

       A.  Doppler effect

            1.  Change in wavelength due to motion

            2.  With light

                 a.  Movement away stretches wavelength

                      1.  Longer wavelength

                      2.  Light appears redder

                 b.  Movement toward squeezes wavelength

                      1.  Shorter wavelength

                      2.  Light shifted toward the blue

            3.  Amount of shift indicates rate

                 a.  Large Doppler shift indicates a higher velocity

               b.  Small Doppler shift indicates a slower velocity

       B.  Expanding universe

            1.  Most galaxies exhibit a red shift

                 a.  Moving away

                 b.  Farthest exhibit greatest shift and have a greater velocity

            2.  Discovered

                 a.  In 1929 Edwin Hubble

            3.  Hubble's Law–the recessional speed of galaxies is proportional to their distance

4.      Accounts for red shifts

II.  Big Bang theory

       A.  Accounts for galaxies moving away from us

       B.  Universe once confined to a "point"

            1.  Supermassive

            2.  Dense

            3.  Hot

C.    Big bang marks inception of the universe

            1.  About 13.6 billion years ago

            2.  All matter and space created

D.    Matter moving outward