The Oort Cloud: Crash Course Astronomy #22

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Now that we’re done with the planets, asteroid belt, and comets, we’re heading to the outskirts of the solar system. Out past Neptune are vast reservoirs of icy bodies that can become comets if they get poked into the inner solar system. The Kuiper Belt is a donut shape aligned with the plane of the solar system; the scattered disk is more eccentric and is the source of short period comets; and the Oort Cloud which surrounds the solar system out to great distances is the source of long-period comets. These bodies all probably formed closer into the Sun, and got flung out to the solar system’s suburbs by gravitational interactions with the outer planets.

Table of Contents
Icy Bodies That Can Become Comets 0:27
The Kuiper Belt is a Donut Shape Aligned With the Plane of the Solar System 2:57
The Scattered Disk is More Eccentric and the Source of Short Period Comets 4:26
Oort Cloud Surrounds Our Solar System and is the Source of Long-Period Comets 4:04
These Bodies Probably Formed Near the Sun and Dispersed Through Gravitational Interactions 5:41

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HD Long Exposure Star Timelapse [credit: Jeffrey Beach, Beachfront B-Roll]
Fine Structure in the Comet’s Jets [credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA]
Artist’s impression of a protoplanetary disk. [credit: ESO/L. Calçada – ESO]
Creating Gas Giants [credit: NASA’s Goddard Space Flight Center]
What is a Sungrazing Comet? [credit: NASA’s Goddard Space Flight Center]
Pluto/Neptune Orbit [credit: NASA]
1992 QB1 [credit: ESO]
Eris [credit: W. M. Keck Observatory]
Moons of Pluto [credit: NASA, ESA, and M. Showalter (SETI institute)]
New Horizons Approach [credit: JHUAPL]
Moon [credit: NASA/Goddard Space Flight Center Scientific Visualization Studio]
Pluto [credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute]
Sedna’s Orbit [credit: NASA]
Artist’s Conception of Kuiper Belt [credit: NASA, Wikimedia Commons]
Kuiper Belt World (video) [credit: NASA Kepler Mission/Dana Berry]
Pluto Discovery Plates [credit: Clyde Tombaugh, Lowell Observatory]


Detective says:

How do we know the ages of things regarding the universe? I heard that it was based on the current rate of expansion – but isn't that making a VERY serious error in assuming that the rate of expansion has been a constant since the big bang?

Rainbowdash 36456 says:

makes so much sense

Evolvedgaming says:

If anything the size range for any of these far distant planets would be from 4x the size of Earth to roughly 20x the size of Earth but yet there's more likely to be 2 objects of which one being about 8-12x the Earths mass and the other object about 2-6x the size of Earth.
Also these objects would have to be orbiting either between the Scatter and Kuipler belt or 2x the distance the killer belt orbits at

Caleb Fontenot says:

New Horizions is now orbiting Pluto! (I think)

John C G says:

Good video to get me excited about the horizon probe. I used to think that the horizon probe is a complete waste of money.

Frank K says:

I once witnessed a comet in a clear night sky with the naked eye, it was majestic.

facecrash24 says:

Request!: Another video summarizing some of the information from New Horizon's visit to Pluto and what the implications of this are.

EdEddnEddyonline1 says:

I think the hypothetical red drawf star 'Nemesis' could be out there in the Oort Cloud

Hana Sophia says:

"You could hide a whole planet out there and it would be pretty hard to find."

Could Gallifrey be there?

Ishmael Zivan says:

Oh my ! There is Nibiru !

gabo1841997 says:

The last 2 minutes sound like some Planet X Nibiru alien shit to me.

Kavetrol says:

6:35 HAIL ERIS !!!

zestydude87 says:

And i met a unicorn…

Lawrence Tider says:

Jan Oort ftw!

aureaphilos says:

Phil, I hope you'll consider doing an episode on the Nice Model.  I have had a hard time 1) finding a really good explanation of what set things in motion to result in the movement of the outer planets, and 2) finding a graphic that isn't teeny tiny and over in 2 seconds.  I'm sure you and Thought Café could do a much better job at explaining this theory.  Thanks

Anthony Pirtle says:

So, now that it turns out that Pluto is amazing, does it get its own episode?

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