Asteroids: Crash Course Astronomy #20

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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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Timelapse of Asteroid 2004 FH’s flyby [credit: NASA/JPL Public Domain]
Asteroid Discovery Video [credit: Scott Manley –]
Inner Solar System [credit: Wikimedia Commons]
Kirkwood gaps [credit: Wikimedia Commons]
Ceres, Earth & Moon size comparison,_Earth_%26_Moon_size_comparison.jpg [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]


Georgio16100 says:

Ceres is more of a dwarf planet rather than an asteroid.

Govinda Dasu says:

Congrats Phil in having an asteroid named after you!

Blue Man says:

Nice way of putting Starfox ship in the asteroid belt part.

KnightCraft 130 says:

is it just me or is the intro thing saying (one giant leap for mankind) 20 episodes in and i never knew that

KnightCraft 130 says:

Ceres? Planet or Not. join us in 5 billion years to find out

Mára Mesta says:

8:07 The problem comes when you try to occupy the same volume of space as a car… at the same time… 😀

Tony Tu says:

Isn't Mars crossing Asteroids also called Aten Asteroids?

LordOfNothingreally says:

So you're saying even if I become an amateur astronomer there'll never be an asteroid called "123-3-poopoopeepee"?

MaryamK 65 says:


sonic_man 33 says:

this is my favorite show on youtube

sonic_man 33 says:

thats so cool how he discovered his own astroid

arturo ballesteros says:

Isn't Amy that one astronomer from Ready Jet Go?

Jihyeok Chang says:

Ceres' craters are filled with salt not ice. That is what the shiny stuff are.

Ishita Gupta says:

"The universe is under no obligation to adhere to our expectations" my favourite part in the whole series so far

Hanna Muller says:

Where the frack is the Pluto episode

TryToReadThis says:

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Please go out and vote today or you will regret it your entire life.


Connor Zerka says:

Jebidiah, Bill and Bob.

Mileena and Scorpion Fan says:

Fav crash course Ceres

Kenneth Moureau says:

3:15 YEAY! Starfox! lol

Samar Obeida says:

I love phil !!!!!

Soumyajit Sinha Roy says:

good to know u have a astroid name on urs… congrats!!

communistjesus says:

00:52 !!!NEWS FLASH!!! " The planet between Mars, and Jupiter is NIBURU.". HAHAHAHA NIBURU XO)XO) HAHAHA..
Yes, from the IDIOTS A.K.A. DONALD TRUMP or Hillary Clinton SUPPORTERS. comes " Planet Niburu ".. Yes, these are THE SAME PEOPLE that in the FREAKING XXI century still think that: " The earth is flat ". The same MORONS who were convinced by an ex Playboy model HO to stop vaccinating their children because she says that: " Vaccines , to prevent childhood illnesses,such as Measles , can affect the child's mind"… After all, who knows more about childhood illness prevention and their side effects ??.. Individuals who have spent the ENTIRE professional lives devoted to the study, and eradication of these illnesses , or a ne'er-do-well-RAPIDLY AGING 57UT/H0BA6 whose only claim to fame was showing her now SA661N6 naughty bits to the world??… Oh, if these are my choices, " I will ALWAYS LISTEN to The RAPIDLY AGING 57UT/H0BA6 whose only claim to fame was showing her now SA661N6 naughty bits to the worldnamed
Jenny W h 0r3 carthy ".. .. COME ON NIBURU believing, Donald Chump – Hill Hill supporting, Jenny
W h0r3carthy advice taking people USE YOUR GRAY MATTER AND THINK.. !!! THINK DARN IT!!!

Cathy B says:

Is Ceres an asteroid or also a dwarf planet? I'm confuse 🙁 says:

165347Philplait !!! Awesome !!!!

francisco cochua says:

Aten/Atin is ours in my language

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