Course content

0h12m

Introduction to Astronomy: Crash Course Astronomy #1

Welcome to the first episode of Crash Course Astronomy. Your host for this intergalactic adventure is the Bad Astronomer himself, Phil Plait. We begin with answering a question: "What is astronomy?"

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Table of Contents:
What is Astronomy? 3:00
Who Studies Astronomy? 3:50
Origins & Developments 6:52

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Photos:
http://commons.wikimedia.org/wiki/File:Earth_cutaway.png
http://en.wikipedia.org/wiki/Earth%27s_magnetic_field#mediaviewer/File:Geodynamo_Between_Reversals.gif
http://en.wikipedia.org/wiki/Geomagnetic_storm#mediaviewer/File:Magnetosphere_rendition.jpg
http://en.wikipedia.org/wiki/Saturn#mediaview

0h11m

Naked Eye Observations: Crash Course Astronomy #2

Today on Crash Course Astronomy, Phil invites you to head outside and take a look at all the incredible things you can see with your naked eye.

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Table of Contents:
Naked Eye Observations 0:28.4
Constellations 3:09.7
The Color of Stars 2:44.5
View of the Stars 7:25

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PHOTOS
http://www.eso.org/public/images/potw1333a/
http://commons.wikimedia.org/wiki/File:3_Solar_Interstellar_Neighborhood_(ELitU).png
http://www.spacetelescope.org/images/heic0206j/
http://www.spacetelescope.org/images/heic0720c/
http://upload.wikimedia.org/wikipedia/commons/3/36/Orion_tjt.jpg
http://hubblesite.org/newscenter/archive/re

0h09m

Cycles in the Sky: Crash Course Astronomy #3

This week we build on our naked eye observations from last week and take a look at the cyclical phenomena that we can see at work in the universe.

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Table of Contents:
Naked Eye Observations 0:28.4
Constellations 3:09.7
The Color of Stars 2:44.5
View of the Stars 7:25

--

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PHOTOS
http://en.wikipedia.org/wiki/Right_ascension#mediaviewer/File:Stars_and_ra.png
http://en.wikipedia.org/wiki/File:Ecliptic_path.jpg
http://commons.wikimedia.org/wiki/File:Sagittarius_Hevelius.jpg
http://en.wikipedia.org/wiki/Scorpius#mediaviewer/File:Sidney_Hall_-_Urania%27s_Mirror_-_Scorpio.jpg
http://en.wikipedia.org/wiki/Libra

0h09m

Moon Phases: Crash Course Astronomy #4

In this episode of Crash Course Astronomy, Phil takes you through the cause and name of the Moon's phases.

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Why the Moon Has Phases 0:36.1
Spheres in Orbit 1:05.4
Name of the Moon Phases 2:25.5
How We See It 7:48.2

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PHOTOS
http://en.wikipedia.org/wiki/Moon#mediaviewer/File:FullMoon2010.jpg
https://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=1879
http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_30p/moon.0505.jpg
http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_30p/moon.0553.jpg
http://svs.gsfc.nasa.gov/vis/a000000/a004200/a004236/frames/730x730_1x1_

0h10m

Eclipses: Crash Course Astronomy #5

The big question in the comments last week was, "BUT WHAT ABOUT ECLIPSES?" Today, Phil breaks 'em down for you.

This episode is sponsored by Squarespace: http://www.squarespace.com/crashcourse

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As promised, Phil's sun spotting recommendations:

Astronomers Without Borders (charitable org): http://store.astronomerswithoutborders.org/index.php?main_page=product_info&cPath=8&products_id=3

Rainbow Symphony glasses (I have these myself): http://www.rainbowsymphony.com/soleclipse.html

Wide variety of viewers from Rainbow Symphony: http://www.eclipseglasses2017.com/buy-eclipse-glasses

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Solar Eclips 0:59
Lunar Eclipse 1:03
Moon's Orbit 1:23
Size of the Earth and Moon 8:24

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0h12m

Telescopes: Crash Course Astronomy #6

Today Phil explains how telescopes work and offers up some astronomical shopping advice.

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How Telescopes Work 1:07
Refractors vs Reflectors 2:50
Technology and the Light Spectrum 7:45

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PHOTOS/VIDEOS
http://en.wikipedia.org/wiki/Galileo_Galilei#mediaviewer/File:Justus_Sustermans_-_Portrait_of_Galileo_Galilei,_1636.jpg
http://en.wikipedia.org/wiki/Human_eye#mediaviewer/File:Human_eye_with_blood_vessels.jpg
http://en.wikipedia.org/wiki/Refracting_telescope#mediaviewer/File:Refractor_Cincinnati_observatory.jpg
http://commons.wikimedia.org/wiki/File:Positive_lens_2.svg
http://www.eso.org/public/images/yb

0h10m

The Gravity of the Situation: Crash Course Astronomy #7

In today's episode, Phil looks at how gravity plays out across the universe.

This episode is sponsored by Squarespace: http://www.squarespace.com/crashcourse

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Gravity is a Force 2:17
Different Types of Orbit 3:41
Escape Velocity 5:30
Weightless Mass 7:03

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PHOTO/VIDEO CREDITS
First photo by Roscosmos / NTSOMZ/ SRC "Planeta" / zelenyikot.livejournal.com
http://www.slate.com/blogs/bad_astronomy/2013/09/25/earth_at_equinox_elektro_l_view_of_the_earth_from_space.html
http://commons.wikimedia.org/wiki/File:Portrait_of_Robert_Hooke_with_a_book,_spring_and_quill.JPG
http://en.wikipedia.org/wiki/Isaac_Ne

0h09m

Tides: Crash Course Astronomy #8

Today Phil explores the world of tides! What is the relationship between tides and gravity? How do planets and their moons become tidally locked? What would happen if you were 300km tall? Important questions.

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Gravity Over Distance 0:44
Tidal Force Parameters 1:35
Battle of the Bulges 2:55
Tidal Lock 6:17

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PHOTO/VIDEO CREDITS
Photo & video credit: "NASA's Scientific Visualization Studio"
http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=4236 Photo credit: "NASA's Scientific Visualization Studio"
https://www.flickr.com/photos/gsfc/8556665115/in/photostream/
http://svs.gsfc.nasa.gov/cgi-bin/details.

0h10m

Introduction to the Solar System: Crash Course Astronomy #9

In today's Crash Course Astronomy, Phil takes a look at the explosive history of our cosmic backyard. We explore how we went from a giant ball of gas to the system of planets and other celestial objects we have today.

This episode is sponsored by Squarespace: http://www.squarespace.com/crashcourse

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Makeup of a Solar System 2:38
From Gas to a Disc 5:36
Planet Formation Depends on Distance to Sun 7:14
Motion of a System 8:21

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PHOTO/VIDEO CREDITS
Sun: http://www.nasa.gov/sites/default/files/706436main_20121114-304-193blend_m6-orig_full.jpg [credit: NASA/ESA]
Jupiter: http://www.jpl.nasa.gov/images/hub

0h12m

The Sun: Crash Course Astronomy #10

Phil takes us for a closer (eye safe!) look at the two-octillion ton star that rules our solar system. We look at the sun's core, plasma, magnetic fields, sunspots, solar flares, coronal mass ejections, and what all of that means for our planet.

This episode is sponsored by Squarespace: http://www.squarespace.com/crashcourse

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The Sun is a Star 1:28
Plasma's Magnetic Fields 6:11
Sunspots, Solar Flares, and Coronal Mass Ejections 7:09
How the Earth Reacts 9:18

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PHOTO/VIDEO CREDITS
Hubble extrasolar planet search field in Sagittarius: http://www.spacetelescope.org/images/heic0612d/ [credit: NASA, ES

0h10m

The Earth: Crash Course Astronomy #11

Phil starts the planet-by-planet tour of the solar system right here at home, Earth.

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Table of Contents
Earth is a Planet 0:03
Layers of Earth 1:25
The Magnetic Field 5:10
Atmosphere and the Human Influence 6:14

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PHOTOS/VIDEOS
Planets:
Mercury: http://apod.nasa.gov/apod/ap080116.html
Venus: http://www.msss.com/all_projects/magellan.php
Earth: http://earthobservatory.nasa.gov/IOTD/view.php?id=36019
Mars: http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-mars.html
Jupiter: http://www.nasa.gov/mission_pages/cassini/multimedia/pia04866.html
Saturn: http://www.slate.com/content/dam/slate/blogs/bad_

0h09m

The Moon: Crash Course Astronomy #12

Join Phil for a tour of our capital-M Moon, from surface features, inside to the core, and back in time to theories about its formation.

This episode is brought to you by Squarespace: http://www.squarespace.com/crashcourse

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Table of Contents
Many Millions of Moons 0:27
Big Impact on Little Earth 3:42
Craters and Maria 2:15
Water on the Moon? H2O Yeah! 8:06

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PHOTOS/VIDEOS
Moon Phase 47.7% http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=3894 [credit: NASA/Goddard Space Flight Center Scientific Visualization Studio]
The Blue Marble http://visibleearth.nasa.gov/view.php?id=57723 [credit: Credit: NA

0h10m

Mercury: Crash Course Astronomy #13

Mercury is the closest planet to the sun. It has no atmosphere and is, as such, covered in craters. It's also incredibly hot but, surprisingly, has water ice hiding beneath its surface.

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Table of Contents
Closest Planet to the Sun 0:03
Rotation Locked to its 2 to 3 Orbit Ratio 3:10
Deep Crater Water Ice 8:39

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PHOTOS/VIDEOS
Mercury relief in Olomouc: http://commons.wikimedia.org/wiki/File:Mercury_relief_in_Olomouc.jpg [credit: Michal Ma?as]
Mercury: Phil Plait
Mercury in color: http://en.wikipedia.org/wiki/File:Mercury_in_color_c1000_700_430.png [credit: NASA/Johns Hopkins University Applied Physic

0h10m

Venus: Crash Course Astronomy #14

Venus is a gorgeous naked-eye planet, hanging like a diamond in the twilight -- but it’s beauty is best looked at from afar. Even though Mercury is closer to the sun, Venus is the hottest planet in the solar system, due to a runaway greenhouse effect, and has the most volcanic activity in the solar system. Its north and south poles were flipped, causing it to rotate backwards and making for very strange days on this beautiful but inhospitable world.

This episode is brought to you by Squarespace http://www.squarespace.com/crashcourse

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Table of Contents
Venus’s Size and Atmosphere 3:09
Hottest Planet in the Solar System 4:04
Slow Clockwise Rotation 6:02
Tremendous Volcanic Activity 8:31

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0h10m

Mars: Crash Course Astronomy #15

The fourth planet from the sun and the outermost of the terrestrial planets, Mars has long been a popular spot for missions and imagination. Phil walks you through the planet's topography, core, and features. We'll take a look back to Mars's past and makes predictions for its future, including the possibilities for human life.

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Table of Contents
Mars is Colder and Smaller Than Earth 0:56
Polar Ice Caps 3:29
Rusty & Dusty 1:16
Huge Volcanoes 2:32
Mars’s Past Geography 6:33

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PHOTO/VIDEO SOURCES
Planets https://en.wikipedia.org/wiki/Solar_System#/media/File:Planets2013.jpg [credit: Wikimedia Commons]

0h10m

Jupiter: Crash Course Astronomy #16

Jupiter is the biggest planet in our solar system. The gas giant is NOT a failed star, but a really successful planet! It has a dynamic atmosphere with belts and zones, as well as an enormous red spot that’s actually a persistent hurricane. Jupiter is still warm from its formation, and has an interior that’s mostly metallic hydrogen, and it may not even have a core.

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Table of Contents
Jupiter is the Biggest Planet in Our Solar System 0:28
Belts and Zones 1:33
Persistent Hurricane 2:32
Metallic Hydrogen Interior 4:03
Fast Spin 0:49
Not a Failure 6:17

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PHOTO/VIDEO SOURCES
Jupiter http://www.spacetel

0h10m

Jupiter's Moons: Crash Course Astronomy #17

Before moving on from Jupiter to Saturn, we’re going to linger for a moment on Jupiter’s moons. There are 67 known moons, and 4 huge ones that we want to explore in greater detail. Ganymede is the largest - larger, in fact, than any other moon in the solar system and the planet Mercury! Callisto, orbiting the farthest out, is smaller but quite similar to Ganymede in many ways. Io, meanwhile, is most noteworthy for its tremendous volcanic activity. There’s also water on Ganymede and Europa!

This episode was brought to you by Squarespace http://www.squarespace.com/crashcourse

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Table of Contents
Jupiter Has 67 Moons (4 Big Ones) 0:12
Ganymede is the Largest 1:15
Io is Riddled With Volcanoes 3:16
Europa Has an Undersurface Ocean 4:48
Io, Europa, and Ganymede Interact Gravitationally 3:48
Known Unknowns 8:06

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Face

0h12m

Saturn: Crash Course Astronomy #18

Saturn is the crown jewel of the solar system, beautiful and fascinating. It is a gas giant, and has a broad set of rings made of ice particles. Moons create gaps in the rings via their gravity. Saturn has dozens of moons, including Titan, which is as big as Mercury and has a thick atmosphere and lakes of methane; and Enceladus which has an undersurface ocean and eruptions of water geysers. While we are still uncertain, it is entirely possible that either or both moons may support life.

This episode was brought to you by Squarespace http://www.squarespace.com

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Table of Contents
Saturn is a Gas Giant 0:33
Moons Create Gaps in the Ice Rings 5:17
Dozens of Moons 6:18
Titan’s Methane Lakes 7:56
Enceladus’s Water Geysers 8:33
Life Potential 9:30

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0h12m

Uranus & Neptune: Crash Course Astronomy #19

Today we’re rounding out our planetary tour with ice giants Uranus and Neptune. Both have small rocky cores, thick mantles of ammonia, water, and methane, and atmospheres that make them look greenish and blue. Uranus has a truly weird rotation and relatively dull weather, while Neptune has clouds and storms whipped by tremendous winds. Both have rings and moons, with Neptune’s Triton probably being a captured iceball that has active geology.

This episode was brought to you by Squarespace http://www.squarespace.com/crashcourse

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Table of Contents
Ice Giants With Small Rocky Cores 2:18
Thick Mantles of Ammonia, Water, and Methane 1:53
Atmospheres Makes Them Look Green And Blue 2:53
Uranus Has Dull Weather 3:35
Neptune Has Active Weather 7:19
Both Have Rings And Moons 5:12

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0h11m

Asteroids: Crash Course Astronomy #20

Now that we’ve finished our tour of the planets, we’re headed back to the asteroid belt. Asteroids are chunks of rock, metal, or both that were once part of smallish planets but were destroyed after collisions. Most orbit the Sun between Mars and Jupiter, but some get near the Earth. The biggest, Ceres is far smaller than the Moon but still big enough to be round and have undergone differentiation.

CORRECTION: In the episode we say that 2010 TK7 is 800 km away. However, 2010 TK7 stays on average 150 million kilometers from Earth, but that can vary wildly.
Sorry about that!

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Table of Contents
Asteroids Are Chunks of Rock, Metal, or Both 1:45
Most Orbit the Sun Between Mars and Jupiter 7:16
Ceres is Far Smaller Than the Moon, But Large Enough to be Round 3:43

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