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Re: [Phys-l] CMB and TV



On 3/28/2012 12:15 PM, Bernard Cleyet wrote:
On 2012, Mar 28, , at 09:40, Anthony Lapinski wrote:

I'm teaching about cosmology soon in my astronomy class. I know that the
CMB (cosmic microwave background) is about 2.7 K. Using Wien's Law, this
radiation is most intense around 1 mm. This corresponds to an EM frequency
of about 300 GHz. I once heard that some of the snow/static in between TV
channels is made up of the CMB. How much? Does anyone know what percent
this would be? I figure UHF/VHF channels are around 300 MHz, so maybe
divide to get 0.001 = 0.1%. Does this make sense?


11th slide:

http://www.markcwyman.com/comptonlectures/Lecture4.pdf


This lecture slide offered a graph for CMB: it gives a peak intensity at
around 5 waves per cm. The intensity was given in units of
ergs/cm^2.sr.sec.cm^-1

Almost as amusing as these units was the tongue in cheek comment beneath

"It is important when answering such questions [how to measure CMB] to
be objective, to look at each experiment on its own merits, and not to
be swayed by any personal biases. So my answer is the Balloon-borne
Anisotropy Measurement at UBC, and the Low Frequency Instrument part of
the Planck mission (both of which I am coincidentally involved with). "


/Douglas Scott/* dscott@.ubc.ca *Last revised: 13th
December 1999

*********

Brian W

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