Comets: Crash Course Astronomy #21

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 on 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.

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Chapters:
Introduction: Comets 00:00
Comets = Dirty Snowballs 1:19
Comets Have Two Tails 2:52
Short-Term vs Long-Term Comets 4:35
Where do comets come from? 5:06
Comets Up-Close 6:17
What Happens When Comets Hit Earth? 9:15
Review 10:59
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PHOTOS/VIDEOS
Comet McNaught [credit: Phil Plait]
[credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)]

[maelstrom]

I wish this show would never stop. Phil rocks!

[aabhinnav]

I've mentioned earlier that
A: I love Crash Course and
2: Bring back Phil!

[ashleysmall]

A: Great video.
2: Thanks for the upload.

[DataCabe]

I foresee an entire outtakes episode of Phil trying to pronounce "67P/Churyumov–Gerasimenko."

[amandawhite]

I told myself, I'm going to go into the comment section and it's going to be full of
A: people quoting Phil about
2: this

[MrGeekGamer]

This is my favourite Crash Course series by far. I've even bought a telescope!

[zahincastro]

The part on the Amino Acids found in the Coma of the Comet....Blew my mind. We might be part Alien....Awesome. This is why I watch Crash Course, Love You Guys. I feel compelled to donate right now.

[norhansabry]

please do not stop making these episodes
and please make more academic ones with all the math behind astronomy and all the practical work some of us really wants to learn astronomy

[TheFireflyGrave]

Sublimation is one of my favorite words.  Just sounds so... sublime.

[MaessyChan]

So far, I have wathced 21 episode of this series in three days on my free time. I'm very new about Astronomy and I love the way Mr.Phil Plait delivered these knowledge. And also, I love his English (I'm still improving my English language too). Over all, this is the first series in youtube that I love so far. Thanks to all of the team who have created this video and share it with us!! 💕🙏

[Tazfel]

a note on the resourcefulness of this channel; not only does it showcase useful information found through internet research, but they also provide credits to the source of visual resources shown in the video. Please keep doing this CrashCourse, thank you!!!

[mentpeki]

I watch your wonderful videos before I sleep, hoping to dream of the stars and the universe. Of course Phil is narrating the voyage hahaha so its less scary to be in the "unknown". Phil is just so cheerful and enthusiastic that even if your about to get sucked in by a black hole he would probably have a great explanation for it, and you'll still be okay! Thank you for making videos that expands our comprehension of reality! Really deeply appreciate it. ❤🤓

[Pyrex]

a) comets have lots of ice in them, and 2) they also get really close to Earth sometimes. LOL

[Tullio]

I remember seeing comet Hale-Bopp in the back garden with my dad, even with all the light pollution. That's a moment I won't soon forget :)

[crackrat]

He said "a" and then "2".. Good job crash course xD

[pwersave]

"...what gets me are the philosophical ramiications of this. When we look into space, when we examine our celestial neighbours, when we send probes, we are looking at our own origins". Just brilliant Phil!!

[EugeneKhutoryansky]

Very good information.  I just recently subscribed to this channel.  Thanks.

[whichdoktor]

I began this series not really liking Phil, main because he wasn't Hank. But I stuck with it because I love astronomy, and 'lo and behold! I actually started seeing more of Phil's enthusiasm and it started rubbing off on me more. I am now in orbit around Phil. Please make more videos like this (especially college-level stuff).

Sincerely,
A happy fan

[Ritermann]

What I like about this channel is, that you care about design. It just feels good to watch it! Thanks for putting effort into it.

[Esth.]

Thanks for the Astronomy Crash Course, it's great and I really start to like astronomy more with each episode :D don't stop uploading!