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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!

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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PHOTOS/VIDEOS
Timelapse of Asteroid 2004 FH’s flyby [credit: NASA/JPL Public Domain]
Asteroid Discovery Video [credit: Scott Manley – [email protected]]
Inner Solar System [credit: Wikimedia Commons]
Kirkwood gaps [credit: Wikimedia Commons]
Ceres, Earth & Moon size comparison [credit: NASA]
Dawn Glimpses Ceres’ North Pole [credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA]
Ceres cutaway [credit: NASA, ESA, and A. Feild (STScI)]
Bright Spot on Ceres Has Dimmer Companion [credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA]
Vesta [credit: NASA/JPL-Caltech/UCAL/MPS/DLR/IDA]
Lutetia [credit: ESA]
Gaspra [credit: NASA]
Steins [credit: ESA/Osiris]
Mathilde [credit: NEAR Spacecraft Team, JHUAPL, NASA]
Ida [credit: NASA/JPL]
Kleopatra [credit: Stephen Ostro et al. (JPL), Arecibo Radio Telescope, NSF, NASA]
An artist’s conception of two Pluto-sized dwarf planets in a collision around Vega. [credit: NASA/JPL-Caltech/T. Pyle (SSC)]
Itokawa [credit: ISAS, JAXA]
An artist’s illustration showing two asteroid belts and a planet orbiting Epsilon Eridani [credit: NASA/JPL-Caltech]
Near-Earth Asteroids [credit: NASA/JPL-Caltech]
Lagrange Points Diagram [credit: Wikimedia Commons]
TK7 [credit: NASA/JPL-Caltech/UCLA]
165347 Philplait [credit: Larry Denneau/Pan-STARRS via Amy Mainzer]