Astronomy

0% Complete
0 out of 65 Lessons
0% Complete
0 out of 4 Exams
Previous Lessons
Open Chapter Ch. 1: A Modern View of the Universe
Lesson #1 The Scale of the Universe
Incomplete Assignment Study Questions for Lesson 1
Lesson #2 The History of the Universe
Incomplete Assignment Study Questions for Lesson 2
Lesson #3 Spaceship Earth
Incomplete Assignment Study Questions for Lesson 3
Open Chapter Ch. 2: Discovering the Universe for Yourself
Lesson #4 Patterns in the Night Sky
Incomplete Assignment Study Questions for Lesson 4
Lesson #5 The Reason for Seasons
Incomplete Assignment Study Questions for Lesson 5
Lesson #6 The Moon, our Constant Companion
Incomplete Assignment Study Questions for Lesson 6
Lesson #7 Ancient Mystery of the Planets
Incomplete Assignment Study Questions for Lesson 7
Open Chapter Ch. 3: The Science of Astronomy
Lesson #8 The Ancient Roots of Science
Incomplete Assignment Study Questions for Lesson 8
Lesson #9 Ancient Greek Science
Incomplete Assignment Study Questions for Lesson 9
Lesson #10 The Copernican Revolution
Incomplete Assignment Study Questions for Lesson 10
Lesson #11 The Nature of Science
Incomplete Assignment Study Questions for Lesson 11
Open Chapter Ch. 4: Understanding Motion, Energy, and Gravity
Lesson #12 Describing Motion
Incomplete Assignment Study Questions for Lesson 12
Lesson #13 Newton's Laws of Motion
Incomplete Assignment Study Questions for Lesson 13
Lesson #14 Conservation Laws in Astronomy
Incomplete Assignment Study Questions for Lesson 14
Lesson #15 The Force of Gravity
Incomplete Assignment Study Questions for Lesson 15
Open Chapter Ch. 5: Light: The Cosmic Messenger
Lesson #16 Basic Properties of Light and Matter
Incomplete Assignment Study Questions for Lesson 16
Lesson #17 Learning from Light
Incomplete Assignment Study Questions for Lesson 17
Lesson #18 Collecting Light with Telescopes
Incomplete Assignment Study Questions for Lesson 18
Exam Exam 1
Open Chapter Ch. 6: Formation of the Solar System
Lesson #19 A Brief Tour of the Solar System
Incomplete Assignment Study Questions for Lesson 19
Lesson #20 The Nebular Theory of Solar System Formation
Incomplete Assignment Study Questions for Lesson 20
Lesson #21 Explaining the Major Features of the Solar System
Incomplete Assignment Study Questions for Lesson 21
Lesson #22 The Age of the Solar System
Incomplete Assignment Study Questions for Lesson 22
Open Chapter Ch. 7: Earth and the Terrestrial Worlds
Lesson #23 Earth as a Planet
Incomplete Assignment Study Questions for Lesson 23
Lesson #24 The Moon and Mercury: Geologically Dead
Incomplete Assignment Study Questions for Lesson 24
Lesson #25 Mars, a Victim of Planetary Freeze Drying
Incomplete Assignment Study Questions for Lesson 25
Lesson #26 Venus, a Hothouse World
Incomplete Assignment Study Questions for Lesson 26
Lesson #27 Earth as a living planet
Incomplete Assignment Study Questions for Lesson 27
Open Chapter Ch. 8: Jovian Planet Systems
Lesson #28 A Different Kind of Planet
Incomplete Assignment Study Questions for Lesson 28
Lesson #29 A Wealth of Worlds: Satellites of Ice and Rock
Incomplete Assignment Study Questions for Lesson 29
Open Chapter Ch. 9: Asteroids, Comets, and Dwarf Planets
Lesson #30 Classifying Small Bodies
Incomplete Assignment Study Questions for Lesson 30
Lesson #31 Asteroids
Incomplete Assignment Study Questions for Lesson 31
Lesson #32 Comets
Incomplete Assignment Study Questions for Lesson 32
Lesson #33 Pluto and the Kuiper Belt
Incomplete Assignment Study Questions for Lesson 33
Lesson #34 Cosmic Collisions - Small Bodies vs Planets
Incomplete Assignment Study Questions for Lesson 34
Open Chapter Ch. 10: Other Planetary Systems
Lesson #35 Detecting Planets Around Other Stars
Incomplete Assignment Study Questions for Lesson 35
Lesson #36 The Nature of Planets Around Other Stars
Incomplete Assignment Study Questions for Lesson 36
Lesson #37 The Formation of Other Planetary Systems
Incomplete Assignment Study Questions for Lesson 37
Exam Midterm Exam
Open Chapter Ch. 11: Our Star
Lesson #38 The Sun, Our Star
Incomplete Assignment Study Questions for Lesson 38
Lesson #39 Nuclear Fusion in the Sun
Incomplete Assignment Study Questions for Lesson 39
Lesson #40 Sun-Earth Connection
Incomplete Assignment Study Questions for Lesson 40
Open Chapter Ch. 12: Surveying the Stars
Lesson #41 Properties of Stars
Incomplete Assignment Study Questions for Lesson 41
Lesson #42 Patterns in the Stars
Incomplete Assignment Study Questions for Lesson 42
Lesson #43 Star Clusters
Incomplete Assignment Study Questions for Lesson 43
Open Chapter Ch. 13: Star Stuff
Lesson #44 Star Birth
Incomplete Assignment Study Questions for Lesson 44
Lesson #45 Life as a Low Mass Star
Incomplete Assignment Study Questions for Lesson 45
Lesson #46 Life as a High Mass Star
Incomplete Assignment Study Questions for Lesson 46
Open Chapter Ch. 14: The Bizarre Stellar Graveyard
Lesson #47 White Dwarfs
Incomplete Assignment Study Questions for Lesson 47
Lesson #48 Neutron Stars
Incomplete Assignment Study Questions for Lesson 48
Lesson #49 Black Holes: Gravity’s Ultimate Victory
Incomplete Assignment Study Questions for Lesson 49
Exam Exam 3
Open Chapter Ch. 15: Our Galaxy
Lesson #50 The Milky Way Revealed
Incomplete Assignment Study Questions for Lesson 50
Lesson #51 Galactic Recycling
Incomplete Assignment Study Questions for Lesson 51
Lesson #52 The History of the Milky Way
Incomplete Assignment Study Questions for Lesson 52
Open Chapter Ch. 16: A Universe of Galaxies
Lesson #53 Islands of Stars
Incomplete Assignment Study Questions for Lesson 53
Lesson #54 Distances of Galaxies
Incomplete Assignment Study Questions for Lesson 54
Lesson #55 Galaxy Evolution
Incomplete Assignment Study Questions for Lesson 55
Lesson #56 The Role of Supermassive Black Holes
Incomplete Assignment Study Questions for Lesson 56
Open Chapter Ch. 17: The Birth of the Universe
Lesson #57 The Big Bang Theory
Incomplete Assignment Study Questions for Lesson 57
Lesson #58 Evidence for the Big Bang
Incomplete Assignment Study Questions for Lesson 58
Lesson #59 The Big Bang and Inflation
Incomplete Assignment Study Questions for Lesson 59
Open Chapter Ch. 18: Dark Matter, Dark Energy, and the Fate of the Universe
Lesson #60 Unseen Influences in the Cosmos
Incomplete Assignment Study Questions for Lesson 60
Lesson #61 Structure Formation
Incomplete Assignment Study Questions for Lesson 61
Open Chapter Ch. 19: Life in the Universe
Lesson #62 Life on Earth
Incomplete Assignment Study Questions for Lesson 62
Lesson #63 Life in the Solar System
Incomplete Assignment Study Questions for Lesson 63
Lesson #64 The Search for Extraterrestrial Intelligence
Incomplete Assignment Study Questions for Lesson 64
Lesson #65 Interstellar Travel and Implications for Civilizations
Incomplete Assignment Study Questions for Lesson 65
Exam Final Exam

Assignments:

Unfinished Assignment Study Questions for Lesson 59

Lesson Objectives:

- Inflation to explain key features of the universe
- Olbers' paradox



A key feature of the Big Bang Theory is inflation -- the idea that in a fraction of a second, possibly at the end of the GUT era, the universe underwent a dramatic expansion.

What key features of the universe are explained by inflation? While the Big Bang Theory gained wide acceptance because of the strong evidence of the cosmic microwave background and the abundance of helium in the universe, it left three questions unanswered that can be answered by inflation. They are:

Where did the density enhancements that led to galaxies come from? Quantum mechanics states that in energy fields, the distribution of energy is slightly irregular. Inflation would have dramatically blown up those tiny quantum ripples in the early universe to enormous sizes, making them become the density enhancements around which galaxies would form.

Why is the large scale universe nearly uniform? The inflation hypothesis explains why the universe in general is so uniform in temperature and density by saying that distant regions of our observable universe today were once close enough to exchange radiation.

Why is the geometry of the universe flat? Einstein's theory of relativity says that matter and energy produce curvature of spacetime, but all studies seem to indicate that the large-scale geometry of the universe is flat. Inflation explains this flatness - just like a balloon seems flatter the larger it is blown up, the universe expanded so much that it appears flat.

Given that the concept of inflation offers convenient explanations for many features of the universe, how do we know if inflation really happened? The idea of inflation makes specific predictions about what we should see in the cosmic microwave background -- patterns in the temperature that have been confirmed.



Olbers' paradox states that if the universe were infinite, unchanging, and everywhere the same, then the entire night sky would be bright, because it would be completely covered with stars. If stars are farther away, they will be less bright but more numerous.

The Big Bang Theory explains why the sky is dark - the universe began at a particular moment, so it is not old enough for the light from some stars to have arrived.