GEOSCI 100 Lecture Notes - Lecture 18: Edwin Hubble, Big Crunch
9 May 2018
School
Department
Course
Professor
4-3-18
Beginnings (with Musical Guest)
*Act 1 - Expansion - 13.7 billion years ago
- “The Big Bang Theory” - galaxies have moved farther away from each other (expanding)
- Marked the origin of the universe
- “The Big Crunch” - hypothesis on whether or not the galaxies will contract
Pair & Share: What would you need to know to determine that the big bang happened?
-you have to know about the velocity (direction and magnitude) in which the galaxies are
moving toward us or away from us
-need to know how far away the galaxies are
•Two Ways to Change a Note
-moving at different speeds
-need to know velocity and distance
*Doppler Effect - an increase (or decrease) in the frequency of sound, light, or other waves as
the source and observer move toward (or away from) each other. The effect causes the sudden
change in pitch noticeable in a passing siren, as well as the redshift seen by astronomers
→ light behaves like a wave
*Measuring Distance with the Parallax Effect - blurry appears to be moving fast, distance
farther away appears not blurry and moving slow
- how we measure stars
*Measuring Distance with Brightness - stars that are closer to us appear to be brighter, farther
away is dimmer
*Edwin Hubble - Astronomer who discovered that there are many galaxies
-proved the Big Bang hypothesis into a THEORY
-acquired data through the largest telescope
*Big Bang Theory: theory that originally all the matter in the universe was concentrated into a
single incredibly tiny point. This began to enlarge rapidly in a hot explosion (called the Big
Bang), and it is still expanding today
Distance B Distance A
------------- > -----------------
13.7 billion years 8 billion years
Document Summary
*act 1 - expansion - 13. 7 billion years ago. The big bang theory - galaxies have moved farther away from each other (expanding) The big crunch - hypothesis on whether or not the galaxies will contract. You have to know about the velocity (direction and magnitude) in which the galaxies are moving toward us or away from us. Need to know how far away the galaxies are: two ways to change a note. *doppler effect - an increase (or decrease) in the frequency of sound, light, or other waves as the source and observer move toward (or away from) each other. The effect causes the sudden change in pitch noticeable in a passing siren, as well as the redshift seen by astronomers. *measuring distance with the parallax effect - blurry appears to be moving fast, distance farther away appears not blurry and moving slow how we measure stars.
