Added: 1 year ago
From: khanacademy
Views: 17,308
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  • This might be a stupid question, but should this theoretically mean that eventually the sky would be compeletely lit up by more and more stars as we begin to receive light from futher and futher from space? Or is this prevented by stars dying at a certain rate?

  • You might cover this in a lecture I haven't watched yet, but what do we see when we try to look at something very slightly closer, very slightly more mature, very slightly "bluer" than the cosmic background radiation?

  • Thumbs Up!

  • great stuff

  • you draw good circles

  • if the universe is expanding at a rate that some of that radiation it never going to reach us than shouldn't there not be any radiation that would reach us? or is the expansion of the universe exponential?

  • @kezthepieman13 thats what i was wondering about tooo....

  • the point at which light will no longer be theoretically detectable is when the wavelength is longer then the observable universe.

  • :)

  • This a fantastic series. Thank you so much for taking these ideas and putting them into videos that anyone (except that britzed guy) can understand. I love them. Absolutely love them and can't stop watching even though it's late here! :)

  • "...some threshold at which we will never get light..." That's a little disappointing. I like to imagine, from a perspective on Earth, a completely "white" sky billions of years from now... a point in time in which the light from all other galaxies has finally reached us. But that's okay... I bet it will still be pretty damn bright, right? Thanks for the awesome videos.

  • I enjoyed your presentation very much. A well presented and understandable lecture. Greetings from The Netherlands

  • You are Awesome!! Thank you sooo much for all your videos!!

  • I did some calculation on the "edge" of our observable universe and it seems that the expansion of space at that approximate point is nearly the speed of light. So my question is this. How is it possible when you said that further on in the future we would see a more red shifted background radiation from beyond our observable universe when it seems that this barrier is actually an event horizon?

  • You are a superb teacher. What do you think of the Schmidt Inversion?

  • I finally have a good understanding cosmic background radiation. Thank you!

  • Sal you just continue to overwhelm me.......!!! Next time i look up at the sky.........., its gonna be a whole new feeling!! Thank you for making this playlist.

  • Redder is double-"d"

  • loving this stuff all the info is totally pointless to me. but its soo interesting i cant stop watching them =] there explained so well too cheers man

  • @theBritzed In case you didn't realise, this is the 18th video of the series.

  • @theBritzed Did you see the rest of the playlist?

  • @theBritzed

    you must be kidding! this guy made me visualize the 4th dimension sphere

  • @theBritzed That's way too harsh.

  • @theBritzed u should make a video explaining it better 0.o

  • @theBritzed Re: forget to mention the basics

    You must be looking at this single video, and not seeing all of the videos that led up to this. This video isn't a stand-alone video, but part of a much longer series in which the basics (Red Shift, Big Bang, Cosmic Time Scales, Receeding Galaxies, etc) have all been spelled out in significant detail.

    If you watch all the videos leading up to this, it makes perfect sense.

    Big Thumbs Up

  • @theBritzed Guess what, I'm a layman and I understood every thing he said. What was that about thumbs down again? There, I see one right next to your comment.

  • @theBritzed What? I've only watched two of his videos and I had no problem understanding anything he said.

  • @theBritzed by "it" I assume you mean electromagnetic waves.... "it's" not perceptible once the wavelenght of "it" is longer then the observable universe... not even theoretically

    the only big thumbs down I see here are the ones on your comment

  • This guy just seems to know about everything!My life seems just meaningless when compare with his

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