Astronomy

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

Assignments:

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Lesson Objectives:

- Scientific thinking
- The oldest science
- Egyptians and time
- Solar and lunar calendars



Scientific thinking is based on everyday observations and trial and error experiments. Science in its modern form requires painstaking attention to detail, testing each piece of information to ensure that it is reliable, having a willingness to discard beliefs that are not consistent with observable facts about the physical world.



Astronomy is considered the oldest science. While it was not practiced the same way in ancient times, there were still amazing achievements in astronomy.

Ancient people used observations of the sky to keep track of time, seasons and to aid in navigation. The length of our day is the time it takes the Sun to orbit the sky once. Ancient peoples used to tell time by observing the Sun's path through the sky. Some cultures used sundials. The Egyptians used obelisks, which functioned as simple clocks. At night time, ancient people also estimated time from the position and phase of the Moon or by analyzing constellations that were visible.

The seven days of the week are named after the seven major astronomical objects that were known in ancient times, including the Sun, Moon, and the five planets easily visible to the naked eye - Mercury, Venus, Mars, Jupiter, and Saturn.



The first known clocks can be traced back to the Egyptians some 4,000 years ago.

The Egyptians were also responsible for creating our framework for hours that we use every day. They divided daytime and nighttime each into 12 equal parts, which came to be 12 hours for a.m. and 12 hours for p.m.

The word 'a.m.' stands for ante meridian which is Latin for "before the middle of the day." The word 'p.m.' stands for post meridian which is Latin for "after the middle of the day."



Many cultures built structures such as the Temple Mayor in modern day Mexico City (formerly the Aztec city called Tenochtitlan) and aligned city buildings with cardinal directions of north, south, east and west to keep track of the rising and setting positions of the Sun. This also helped in tracking seasons.

The first written calendars were based on the Moon. The lunar calendar has the same moon phase on the first day of each month. A lunar calendar has 12 months, with roughly 29 to 30 days per month. A full 12-month lunar calendar has 354 or 355 days, or about 11 days less in a year than a solar calendar. This calendar is still in use in some parts of the world and in the Muslim religion.

Today, we use a solar calendar - one that is synchronized with seasons so that solstices and equinoxes fall approximately on the same days every year. Lunar and solar calendars can be synchronized by using a timing coincidence: the lunar phases repeat on the same solar dates every 19 years. If there is a full moon on Feb 11, 2018, there will be a full moon 19 years later on February 11, 2036. To take advantage of this fact, the Jewish calendar adds a thirteenth month to certain years in order to keep the lunar calendar roughly synchronized to the seasons.