Why is the peak frequency of the Cosmic Microwave Background 160 GHz?

In summary, the peak frequency of the Cosmic Microwave Background is approximately 282 GHz, according to the use of Wien's Displacement and conversion of wavelength to frequency. However, other sources may provide slightly different results due to variations in measuring intensity or power per unit wavelength or frequency.
  • #1
Nim
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What is the peak frequency of the Cosmic Microwave Background?

Using Wien's Displacement (#1) and then converting the wavelength of frequency (#2), I get 282 GHz.

#1. 0.0028977685 / 2.728 = 0.00106223185483871 Meters (1 millimeter)

#2. 299792458 / 0.00106223185483871 = 282228834161.183 Hertz (282 GHz)

This website seems to conclude that it's 160.4 GHz:
http://hypertextbook.com/facts/2004/HeatherFriedberg.shtml

Also, if something isn't a perfect black body, is there an easy way to get a more accurate result? Using the surface temperature of the Sun (5785) I get about 500 nanometers, which is green I believe. I imagined I should have gotten a frequency closer to yellow, around 570 nanometers.
 
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  • #2
I don't think this mismatch has actually something to do with anisotropies or deviations from the blackbody spectrum, but rather with the way that power or intensity are defined or measured per unit wavelength or per unit frequency. This leads to different forms of Wien's law and you have to check the definitions when you read about some "peak frequency". You can read about this here.
 
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  • #3
The hyperphysics website gave 160 GHz as an answer using the linear frequency equation. I just have to use a different constant. Thanks for the help.
 
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FAQ: Why is the peak frequency of the Cosmic Microwave Background 160 GHz?

1. What is the peak frequency of the CMB?

The peak frequency of the CMB, or cosmic microwave background, is around 160.23 GHz (gigahertz). This corresponds to a wavelength of approximately 1.9 millimeters.

2. Why is the peak frequency of the CMB important?

The peak frequency of the CMB is important because it provides valuable information about the early universe. The temperature of the peak frequency is directly related to the density and composition of matter in the universe at that time.

3. How was the peak frequency of the CMB determined?

The peak frequency of the CMB was determined through observations made by the COBE (Cosmic Background Explorer) satellite in 1989 and the WMAP (Wilkinson Microwave Anisotropy Probe) satellite in 2001. These satellites measured the temperature of the CMB at different frequencies, allowing scientists to identify the peak frequency.

4. Does the peak frequency of the CMB change over time?

No, the peak frequency of the CMB does not change over time. It is a remnant of the early universe and has remained constant since its formation.

5. Can we see the peak frequency of the CMB with the naked eye?

No, the peak frequency of the CMB is in the microwave range and cannot be seen with the naked eye. It can only be detected through specialized instruments, such as satellites and radio telescopes.

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