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 31

Lesson Objectives:

- An overview of asteroids
- Types of meteorites
- The asteroid belt



Asteroids are important because many of them remain essentially the same as when they formed, early in the life of our solar system four and a half billion years ago.

All are rocky in composition, but those that are farther from the Sun contain more carbon compounds and water.

The largest asteroid in our solar system is also considered a dwarf planet -- Ceres. It is just under 1000 kilometers in diameter and its mass is nearly equal to all of the other asteroids put together.

That gives you an idea of how small most asteroids are. If you were to add up the mass of all of the asteroids, it would still be less than the mass of our Moon.



In recent years, spacecraft have been sent with the purpose of collecting samples from asteroids. Even without those samples, however, scientists have had access to tens of thousands of asteroid samples that have fallen to the Earth as meteorites.

Meteorites are categorized into primitive meteorites and processed meteorites.

Primitive meteorites are those that are essentially unchanged since the birth of the solar system. They are from the time when solid material first condensed from the solar nebula and are the oldest rocks in the solar system. In addition to telling us how old the solar system is, they provide us with information about the solidified material that accreted to form planets and asteroids.

Processed meteorites are different from primitive meteorites in that they are not original, primitive material. They have undergone change, coming from asteroids that were large enough to have undergone differentiation into a core-mantle-crust structure. They tell us that some asteroids were large enough to have had substantial internal heat and volcanic activity, and when the meteorite is a fragment of a core or mantle of a shattered asteroid, they serve as proof of the internal structure of large worlds such as Earth.



Virtually all planetesimals that formed inside of the orbit of Mars accreted onto one of the terrestrial planets, but those that formed beyond Mars were heavily influenced by Jupiter's gravity. Orbital resonances with Jupiter caused many of them to be kicked out of their orbits -- either to crash into a planet or moon, or even the Sun, or flung out of our solar system altogether.

This interference from Jupiter is also what kept those planetesimals from accreting to form another planet. The asteroid belt originally contained a lot more rocky material than it does now, but orbital resonances with Jupiter disrupted many of their orbits and the asteroid belt lost most of its original mass during billions of years.

Basically, the asteroid belt represents the asteroids in the solar system that survived - they did not get accreted onto an existing planet and they did not get kicked out of their orbits by Jupiter.

Change is always happening, however. Orbital resonances continue to shape asteroid orbits and still lead to asteroid collisions today.