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I am not sure whether the sun originally emits everything in the electromagnetic spectrum, (whatever the relative strengths of each portion might be), but I do read that many waves, including gamma / x-ray, and UVC, are filtered or 'converted' to heat after travelling through solar plasma and atmospheric layers like ozone.

But what I am interested in is the lower end of the spectrum (frequency-wise) - like those we ourselves harness for communication.

Does the sun emit low frequency radiation (below infrared), in the first place, and if so, how much of it - if any - actually reaches us on Earth within that same range?

I am guessing it is either none, or only a very small amount as otherwise I assume it would interrupt severely with our own radio communication here on Earth.

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For the first question, yes. Because the surface of the sun is close to a blackbody emitter, it radiates at all wavelengths below the peak. So radio waves are included. However, the longer the wavelength, the less the power that is put into that portion of the spectrum. Radio is so far from visible light on the EM spectrum that the solar radiation in that area is around 10 or more orders of magnitude weaker.

http://www.windows2universe.org/sun/spectrum/multispectral_sun_overview.html Smoothed Solar Spectral Irradiance

While the earth's atmosphere blocks many portions of the EM spectrum, it's fairly transparent in most of the radio portions. That's how we can do so much radio astronomy on the ground.

http://en.wikipedia.org/wiki/Electromagnetic_spectrum#mediaviewer/File:Atmospheric_electromagnetic_opacity.svg

So most of the radio gets here, but it's so low power that it doesn't interfere much.

Now that's just the "normal" stuff that comes from the calm surface of the sun. The sun is much more complex than that. The sun also has slowly variable radio emissions and periodic bursts. Bursts can cause significant amounts of RFI (Radio Frequency Interference).

http://www.spaceacademy.net.au/spacelink/solrfi/solrfi.htm

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