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Watch Crash Course Astronomy - Season 1 Episode 21 Online!:

Today on Crash Course Astronomy, Phil explains comets. Comets are chunks of ice and rock that orbit the Sun. When they get near the Sun the ice turns into gas, forming the long tail, and also releases... dust that forms a different tail. We’ve visited comets up close and found them to be lumpy, with vents in the surface that release the gas as ice sublimates. Eons ago, comets (and asteroids) may have brought a lot of water to Earth -- as well as the ingredients for life. more

Writing:
  • Phil Plait

Stars:
Release Date: 2015-01-15
Seasons: 1
TMDb: 1 2 3 4 5 8.0/10
  • Language: English
  • Runtime: 12

Other episodes for this season

Introduction to Astronomy
Episode 1 - Introduction to Astronomy
Naked Eye Observations
Episode 2 - Naked Eye Observations
Cycles in the Sky
Episode 3 - Cycles in the Sky
Moon Phases
Episode 4 - Moon Phases
Eclipses
Episode 5 - Eclipses
Telescopes
Episode 6 - Telescopes
The Gravity of the Situation
Episode 7 - The Gravity of the Situat...
Tides
Episode 8 - Tides
Introduction to the Solar System
Episode 9 - Introduction to the Solar...
The Sun
Episode 10 - The Sun
The Earth
Episode 11 - The Earth
The Moon
Episode 12 - The Moon
Mercury
Episode 13 - Mercury
Venus
Episode 14 - Venus
Mars
Episode 15 - Mars
Jupiter
Episode 16 - Jupiter
Jupiter's Moons
Episode 17 - Jupiter's Moons
Saturn
Episode 18 - Saturn
Uranus & Neptune
Episode 19 - Uranus & Neptune
Asteroids
Episode 20 - Asteroids
Comets
Episode 21 - Comets
The Oort Cloud
Episode 22 - The Oort Cloud
Meteors
Episode 23 - Meteors
Light
Episode 24 - Light
Distances
Episode 25 - Distances
Stars
Episode 26 - Stars
Exoplanets
Episode 27 - Exoplanets
Brown Dwarfs
Episode 28 - Brown Dwarfs
Low Mass Stars
Episode 29 - Low Mass Stars
White Dwarfs & Planetary Nebulae
Episode 30 - White Dwarfs & Planetary...
High Mass Stars
Episode 31 - High Mass Stars
Neutron Stars
Episode 32 - Neutron Stars
Black Holes
Episode 33 - Black Holes
Binary and Multiple Stars
Episode 34 - Binary and Multiple Stars
Star Clusters
Episode 35 - Star Clusters
Nebulae
Episode 36 - Nebulae
The Milky Way
Episode 37 - The Milky Way
Galaxies, Part 1
Episode 38 - Galaxies, Part 1
Galaxies, Part 2
Episode 39 - Galaxies, Part 2
Gamma-Ray Bursts
Episode 40 - Gamma-Ray Bursts
Dark Matter
Episode 41 - Dark Matter
The Big Bang, Cosmology Part 1
Episode 42 - The Big Bang, Cosmology P...
Dark Energy, Cosmology Part 2
Episode 43 - Dark Energy, Cosmology Pa...
A Brief History of the Universe
Episode 44 - A Brief History of the Un...
Deep Time
Episode 45 - Deep Time
Everything, The Universe...And Life
Episode 46 - Everything, The Universe....