Galaxies, part 2: Crash Course Astronomy #39

Active galaxies pour out lots of energy, due to their central supermassive black holes gobbling down matter. Galaxies tend not to be loners but instead exist in smaller groups and larger clusters. Our Milky Way is part of the Local Group, and will one day collide with the Andromeda galaxy. Clusters of galaxies also clump together to form superclusters, the largest structures in the Universe. In total, there are hundreds of billions of galaxies in the Universe.

--
Chapters:
Introduction: Active Galaxies 00:00
Active Galaxy Structure: Central Black Hole 2:26
Active Galaxy Structure: Accretion Disks 3:42
The Milky Way's Supermassive Black Hole 5:38
The Local Group 6:45
Miklomeda: Andromeda and the Milky Way Collide! 7:29
Galaxy Clusters 9:47
Superclusters 11:19
How Many Galaxies Are There? 12:32
Review 14:25
--

Want to find Crash Course elsewhere on the internet?

--

PHOTOS/VIDEOS

[evilcam]

I really liked Phil's enthusiasm in this episode. He always is very enthusiastic, but he really nailed that home this time around. I hope future generations looks to this show, and other awesome science oriented educational channels on youtube with the same reverence we look at Cosmos and Connections with.

[SirHenryMaximo]

14:04
"It's easy to think the Universe is too big to comprehend and makes us seem tiny and insignificant in comparison. To me the opposite is true. It's our curiosity about this enormous cosmos that makes us significant. We yearn to learn more, to seek out knowledge. That doesn't makes us small, it makes us vast!"

Phil nailed it!

[mrobusto]

"The universe is mind-crushingly huge. And yet, here we are, a part of it, learning more about it all the time. It's easy to think the universe is too big to comprehend, and makes us seem tiny and insignificant in comparison. To me, the opposite is true. It's our curiosity about this enormous cosmos that makes us significant. We yearn to learn more--to seek out knowledge. That doesn't make us small, it makes us vast."

Now that's damn wonderful.

[rolsonDotcom]

This 45 year old kid loves this series. Space is fascinating! This is a well done series.

[kingkalak]

"I'm significant! Screamed the dust speck."
- Calvin

[Quester]

My face always lights up when I see a new episode of cc astronomy in the subscription list.

[bodnotbod]

The ancient philosopher Marcus Aurelius used to talk about how insignificant we are. He described the world as very small also. I wish he could have been around to witness our advances in knowledge that reveal just how right he was.

[DanielLopes]

Holy crap Phil, your dedication and enthusiasm are truly contagious. Every single episode you write and host is not only extremely entertaining to watch but also deeply mind expanding. You have a gift mate, please never let go, you are doing an immensely important job teaching and spreading this subject.

The day when every single person on our tiny planet is aware of the contents shared in this series, Earth will be an awesome place to live in. We should all help that day come as fast as possible.

Already waiting for the next episode :)

[debries]

the grain of sand thing blew my mind. I thought I had some vague sort of sense for the scale of the universe, and I was proven utterly wrong.

Thanks crash course astronomy!

[irwinwinaris]

I love how passionate he is about his work! This has also changed my view on the universe, I've been thinking more macroscopically lately. Love the series!

[SexualPotatoes]

7:42 "IT'S HEADED RIGHT FOR US"

[Brakvash]

Here goes! (cracks fingers)
Andromeda + Milky Way: Andro Bahn, Andromedan Strip, Andromedan Way
Milky Way + Andromeda: Lactomeda
Elliptical: Milky Haze

[shivaoswal]

Milkomeda? We should Call the combo galaxy...."Magna Unam" which is Latin for "great united one"

[WobblyDave]

If Andromeda doesn't combine with the Milky Way can it be said to be lactose intolerant?

[noxvok]

I prefer the term "Milkdromeda"

[jessetheskaterkid]

amazing! I wasn't even planning on watching the video because it seemed too long... but once I clicked play I just couldn't stop watching. learned a lot. thanks

[biohazard]

Learning about the universe is such a humbling experience, it really makes me feel small and insignificant; but, it also reminds me just how special and fortunate we are to even exist. There's nothing more awe inspiring in looking up at the night sky and wondering how in all that chaos, just by chance, our lives came to be.

[VSPG_SIVANI]

Hats Off CrashCourse Astronomy! This is, emphasizingly, the best cosmological and astronomical series in the history. Hats off Phil Plait!

[franziz]

I love this series more with every episode I watch and I love how enthusiastic you are, Phil. Thanks!!

[TheKatieLily]

It hurts my brain to think that there are over 100, 000, 000, 000 galaxies and people STILL think that we are the only form of life in the universe.