Dark Energy, Cosmology part 2: Crash Course Astronomy #43

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The majority of the universe is made up of a currently mysterious entity that pervades space: dark energy. We don’t know exactly what it is, but we do know that dark energy accelerates the expansion of space. We think this means the Universe will expand forever, even as our view of it shrinks while space expands faster all the time.

Crash Course Astronomy Poster: http://store.dftba.com/products/crashcourse-astronomy-poster


Expanding faster than light:

General expansion:

Table of Contents
Majority of the Universe is Made of Dark Energy 4:35
Dark Energy Accelerates the Expansion of Space 3:42
We Think The Universe Will Expand Forever 5:20

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The Big Bang http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10128 [credit: NASA]
Collision Scenario for Milky Way and Andromeda Galaxy Encounter http://www.nasa.gov/images/content/654284main_i1220bw.jpg [credit: NASA; ESA; A. Feild and R. van der Marel, STScI]
Artist’s impression of vampire star http://www.spacetelescope.org/videos/astro_bn/ [credit: ESO/M. Kornmesser]
Host Galaxies of Distant Supernovae http://www.nasa.gov/sites/default/files/images/593872main_hs-2006-52-a-print.jpg [credit: NASA, ESA, and A. Riess (STScl)]
Dark Energy Expands the Universe http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10135 [credit: NASA]
Expanding Universe http://www.spacetelescope.org/videos/hst15_expanding_universe/ [credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)]
Hubble Ultra Deep Field 2014 http://hubblesite.org/newscenter/archive/releases/2014/27/image/a/ [credit: NASA, ESA, H. Teplitz and M. Rafelski (IPAC/Caltech), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI)]


Bobby Trent says:

hey… so I have a ground breaking theory on black holes. please help me prove it wrong. really. I'm begging

Lynn Amber says:

I do hope we can discover what exactly dark energy is and how to control it, someday! It's destroying everything!

It's not an immediate concern, things like global warming are a more immediate problem. But someday we will have to slow the expansion of the universe, or humanity won't make it. ;_;

Game Over says:

So depressing..

Olcay Alp Bayram says:

How long are you going to take for part 44? Did you get bored of doing this series or what? You used to pump them once every week and it was SWEEEEET.

Anna Nica says:

It's like that episode of Doctor Who where all the stars have disappeared out of the sky and no one believes in the stars except for one little girl. What if stars become like a religion in the future where no one can observe them but people believe they still exist?

SLEEKB Joe says:

so weirdo like a game

SLEEKB Joe says:

when space get expansion my fleet was so speed than you said dark energy >>>>>>>..>>…..>>>>>>>f ??????????<—what is here? f was my fleet / ???????? was un expansion what is here?

Andres Angulo says:

"Expand forever"

Maybe it was misinformation, but I recall, but when I first learned of this stuff, that the universe that 3 potential death scenarios.
1- The Big Crunch, the one that suggested the universe would eventually slow down and contract, and collide, potentially igniting a new Big Bang, in a sort of 'heartbeat' universe. (This one is now obsolete of course)
2- Big Freeze, expansion keeps on, but dark matter and normal matter manage to keep it relatively slow in it's acceleration, so the end result is the black void where everything is cold because all stars have moved too far away from each other.
3- Big Rip, universe expands, increasingly fast, and due to the exponential acceleration, at one point the speed would be such that structures would just…. vaporize as matter cannot hold on against the speed.

While I get the Big Crunch is not a possible scenario anymore, which of the other two is our ultimate fate? Or has there been a new fourth death proposed?

A Small Babby says:

Why is it this way just why

So lame

Nikola Ristovic says:

"..,So we better study it while we can, we may only have a few trillion more years left to figure this out" 😀

I think Phil Plate can talk just about anything and still make it fun and interesting.

redcojiro97 says:

"Only a few trillion years"

saxoman1 says:

2 things:

1. Is the acceleration accelerating (jerk lol)?

2. The prospect that future astronomers may never see galaxies and thus never know they exist (existed) is depressing. However, I wonder what cosmic wonders WE missed for having views the universe 12.7 billion years after its birth. What might we be missing that was observable say, 10 billion years ago? Fascinating to think about!

David Blatch says:

Thank you so much for making this series! Its mind blowing and definitely my favourite at the mo.

naveen kanna says:

These are awesome bunch of videos over internet other than anything. Thanks for Mr.Phil Plait and Crash Course Astronomy team 🙂
And i would love to watch if you guys do video on 'THE WORM HOLE' <3

darkmage07070777 says:

Surprised this episode isn't just 10 seconds long:

"Dark Energy: We have NO clue, people. None. Thanks for watching!"

Miner_Link14 says:

Where is the next video?

Diego Barcellos says:

What a lovely episode!! Got me really amazed.

myles roach says:

late into bro

HLC Gaming says:

His hand expressions are seriously annoying

Damien Green says:

Can you tell what age the universe is from the expansion of space?

MazMazda3 says:

This is sooooo AWESOME, can't put words to it. Please keep them coming.

Corentin Kastenbaum says:

But if space is expanding, is matter expanding? is there larger matter everyday? Why wouldn't gravity change if space enlarge? What is expanding, really?

Pravin Raj says:

waiting 3 weeks for next episode sucks!

m33p0 ojnaran says:

Hey Phil, quick question. I've recently learned (about 10 minutes ago) of a discovery that there might different kinds of type 1a supernovas. Any truth to this and how it affects the expansion rate of the universe?

Looking forward to the next episode.

Brian Kerr says:

alternate view on cosmology based on plasma physics found here  http://www.thunderbolts.info

Corin Katzke says:

Hey phil – you mentioned that for a galaxy to be moving at light speed away from us it needs to be about 13.8 billion light years away. 13.8 billion years is also the age of the universe. Is there a connection there? When the universe is 13.9 billion years old, will a galaxy need to be 13.9 billion light years away to be moving at the speed of light away from us? Thanks.

amir shantia says:

Hey CrashCourse, Can you please make a new series about physics for 2016? You guys make really great videos.

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