Difference between revisions of "Cosmic microwave background"
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'''{{PAGENAME}}''' radiation describes the [[electromagnetic wave]]s that propagate through our entire universe. It is thought to be left over radiation from the [[Big Bang]], but its true origin is unknown. | '''{{PAGENAME}}''' radiation describes the [[electromagnetic wave]]s that propagate through our entire universe. It is thought to be left over radiation from the [[Big Bang]], but its true origin is unknown. | ||
| − | Some believe that the cosmic microwave background contradicts [[relativity]]; it provides a way to irrefutably define what is moving and what is not moving. Since the cosmic microwave background is made of electromagnetic waves, a moving observer will observe a [[Doppler shift]] of the cosmic microwave background, whereas a stationary observer will not. Since the frequency of the cosmic microwave background is known (160.2 GHz <ref>http://www.physorg.com/tags/cosmic+microwave+background/</ref>), the velocity of the observer can easily be calculated. Our very Earth sees a Doppler shift in the cosmic microwave background. | + | Some believe that the cosmic microwave background contradicts [[relativity]]; it provides a way to irrefutably define what is moving and what is not moving. Since the cosmic microwave background is made of electromagnetic waves, a moving observer will observe a [[Doppler shift]] of the cosmic microwave background, whereas a stationary observer will not. Since the frequency of the cosmic microwave background is known (160.2 GHz <ref name="physorg">http://www.physorg.com/tags/cosmic+microwave+background/</ref>), the velocity of the observer can easily be calculated. Our very Earth sees a Doppler shift in the cosmic microwave background. |
| − | The thermal black-body spectrum of the cosmic microwave background is 2.725 K. <ref | + | The thermal black-body spectrum of the cosmic microwave background is 2.725 K. <ref name="physorg" /> |
==Notes== | ==Notes== | ||
Revision as of 03:02, September 12, 2009
Cosmic microwave background radiation describes the electromagnetic waves that propagate through our entire universe. It is thought to be left over radiation from the Big Bang, but its true origin is unknown.
Some believe that the cosmic microwave background contradicts relativity; it provides a way to irrefutably define what is moving and what is not moving. Since the cosmic microwave background is made of electromagnetic waves, a moving observer will observe a Doppler shift of the cosmic microwave background, whereas a stationary observer will not. Since the frequency of the cosmic microwave background is known (160.2 GHz [1]), the velocity of the observer can easily be calculated. Our very Earth sees a Doppler shift in the cosmic microwave background.
The thermal black-body spectrum of the cosmic microwave background is 2.725 K. [1]