The Big Bang, Cosmology part 1: Crash Course Astronomy #42

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Thanks to observations of galaxy redshifts, we can tell that the universe is EXPANDING! Knowing that the universe is expanding and how quickly its expanding also allows us to run the clock backwards 14 billion years to the way the universe began – with a bang.

Crash Course Astronomy Poster:

Table of Contents
Distant Galaxies Show a Red Shift in Their Spectra 2:07
The Universe is Expanding 2:51
This Model is Called “The Big Bang” 5:12
The Universe is Almost 14 Billion Years Old 11:43

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Hubble Goes to the eXtreme to Assemble Farthest-Ever View of the Universe [credit: NASA; ESA; G. Illingworth, D. Magee, and P. Oesch, University of California, Santa Cruz; R. Bouwens, Leiden University; and the HUDF09 Team]
Out of this whirl: The Whirlpool Galaxy (M51) and companion galaxy [credit: NASA, ESA, S. Beckwith (STScI), and The Hubble Heritage Team STScI/AURA)]
Red-Shifts in the Spectra of Extra-glactic Nebuale….83…10H&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf [credit: American Astronomical Society, NASA Astrophysics Data System]
Andromeda [credit: Bill Schoening, Vanessa Harvey/REU program/NOAO/AURA/NSF]
The Big Bang (video) [credit: NASA]
The Sun [credit: NASA/SDO]
Alpha Centauri [credit: ESO/Digitized Sky Survey 2, Acknowledgement: Davide De Martin]
Andromeda [credit: NASA/JPL-Caltech]
Friedmann Universes
Friedmann Equation
Penzias and Wilson stand at the 15 meter Holmdel Horn Antenna that brought their most notable discovery.,_New_Jersey.jpeg [credit: NASA]
Planck CMB [credit: ESA and the Planck Collaboration]
Galaxy Superclusters [credit: Marenostrum Numerical Cosmology Project]


Bob Lawblawblaw says:

Then came 1776, the USA, Trump, and then science was fucked.

pakibukas says:

a big bang occured in the center of grandpa's couch

Thiago Coelho says:

the Universe only being three times as old as Earth is surprising to me, I'd expect it to be relatively much older

Yandere Chan says:

this video is used for my school lecs

Siddhant Garud says:

So if I understood the concept of 'look back time' correctly, so even if there was life in other much older galaxies, we won't know because the light coming from there is just too old? Phil please help, or john green, hank green will also do

Eddie says:

What was here before the Big Bang?

Humayun Khan says:

if space is expanding then the galaxies are also expanding. the rate of that expansion should be similar to the rate at which the distance between them is expanding.. so the question is , is that rate Equal

Jaskaran Sehgal says:

honestly isn't the big bang theroy proven wrong

Skandalos says:

Comparing time today with time 14 billion years ago doesnt make a lot of sense.

nour koudmani says:

ok ok I think i missed something. So since the universe is expanding, what is it expanding into? just nothingness?
whats outside of the universe? sorry if this is a dumb question i think i misunderstood something in the vid

Autumn Rockwood says:

my brain hurts

fizpop01 says:

I still don't understand how space is expanding between galxies even though he said the galaxies aren't moving. Can someone explain that?

LeBuno DeLaVie says:

George lemaitre means george TheMaster, I think he wins the name contest

Brendan Jackson says:

You say that all galaxies are moving away from us (redshift), but in a previous video you stated that the Andromeda galaxy is in fact moving towards us (blueshift) and will collide with our galaxy?

The PineApple says:

Meanwhile in the creationist viewpoint….

Nigama Yaratapally says:

Can you please make a video on multiverse ???

Titansoftime says:

If the universe is expanding and we see galaxies moving away from us, this means that matter is clearly not expanding in scale with space-time, otherwise there would be no change in the perceived distance of galaxies. I find it odd that matter wouldn't expand along with space-time since it's "inside" of it.

Can someone explain this?

tonyb24242424 says:

so, is the topology of the universe in 4 or more dimensions?

Drew McClumpha says:

Does space expand at a constant rate?

the snakeu loves hobi says:

when you love physics and seungri at the same time

Μιχάλης Ασιήκκας says:

Hi. Sorry…i m new at this and so my question might appear a bit naive but, when Phil says that there is no centre to the universe…i can understand it as long as you are standing somewhere in the middle….where where ever you look there are things ti look at….what happens if you are at the very edge?

GraphiteProjekt says:

why the hell would anyone have a expandable ruler.

Marcos Barrera says:

I want to discuss some stuff on what this video says, especially who discovered the evidence for the Big Bang theory and when.

Right now (as of early November of 2016) I NEED to focus on college work that I am falling behind in!  I also have some issues with how the Internet connection works at my home.  I will get back to this video later on, which is why I am going to favorite this video. 

I am also doing favorite this video because it is very interesting and awesome!

Meló Manó says:

A black hole creates a hole new universe. The singularity in its center is the starting point. Each universe creates trillions of new ones. The accurate model is the one we see in biology. And universes have evolved from simpler forms to the ones existing today. Reality is way more mindcrushing than we ever can imagine.

paul mortimer says:

1927 expansion theory of universe made by Georges Lemaitre ( belgian priest and contemporary of Einstein) which replaced the steady state model in the 1960's. I bring this up as the film mentions DARWIN the famous astronomer. ? FKINTITS.

Alecsanderel says:

and people are complaining about gay people.

spike378 says:

so what happens when space between galaxies expand to the maximum point? Does it rebound back or tear space time?

Robert Andersson says:

Thank you very much, Phil Plait and the others at Crash Course Astronomy, for making this video! I have to admit that I already knew most of this from before but one thing I learned was that the expansion of the Universe happened in the shape of a huge American football. I also learned the names of who came up with this idea. I have previously heard scientists like Johannes Kepler, Albert Einstein and Stephan Hawking being credited with coming up with this model, the Big Bang model, but I had never heard Vesto Slipher and George Lemaître before. Thank you very much!

I do have a question though: how did Stephen Hawking contribute to the model of the Big Bang? I have seen his documentary on the topic (‘A Brief History of Everything’) and in that, he kind of clams to have done something important for the Big Bang model. What did he do? Did he figure out the rate of the expansion?

Also, I am a lit disappointed there was no what so ever reference to the TV-show ‘The Big Bang Theory’! I love that show, especially Sheldon Cooper…

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