載入中... 相關課程 Back Quasar Correction 登入觀看 ⇐ Use this menu to view and help create subtitles for this video in many different languages. You'll probably want to hide YouTube's captions if using these subtitles. Quasar Correction 上傳學習單 下載學習單 相關課程 0 / 750 I want make a quick correction to the video on quasars. In that video I said and I mistakenly said that the quasars or that the accretion disk that's really forming or releasing the energy of the quasar, that its releasing energy predominately in the... the xray part of the electromagnetic spectrum. And that was incorrect. Most quasars are actually emitting electromagnetic radiation across the spectrum all the way from xrays... all the way from xrays as high frequency xrays all the way down to infrared. All the way down to infrared. And some quasars even release super high frequency gammarays and they will release low frequency electromagnetic waves all the way down to radio waves. So I just wanted to make that correction. Its not predominately in the x-ray part of the spectrum, its across the spectrum right over here. Its this entire range of the spectrum and sometimes even a wider range. Now the other thing I want to clarify is this is the range of the spectrum thats being emitted. But we have to remember that most or, actually all of these quasars are quite far away. The closest is 780 million light years away. And many of them are many many billions of light years away. And so they are moving away from us at a very fast speed, or... they are getting redshifted becuase the universe is expanding so fast relative to us at that point or that coordinate is moving so fast away from our coordinate. And so even though this is the spectrum that is beeing emitted its all going to be redshifted. Its all going to be redshifted down and so we are going to observe things at a much, at a much lower frequency-- maybe around the radio part of the frequency. So everything will be redshifted down. And thats why these were originally called Quasi stellar radio sources. Any hopefully that clears things up a little bit.