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Physics/Attenuation and blooming for EMF from geosynchronous order

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Question
Let's say you have a geosynchronous Satellite at 2,000 km above the earth, and its emitting some type of directional EMF radiation towards a target on the earth.  I'm interested in learning the attenuation with respect to EMF frequency, and also size of how spread out the surface area is that will receive this EMF on the ground (blooming area).  I specifically want to know if its possible to get any microwaves, IR, ultaviolet, xray's, gamma rays,  through the atmosphere and to know what surface area of the earth will receive this energy, one city block or instance or a pin hole for each emf frequency.

Answer
Of course it's possible to get EM waves through the atmosphere. They come through all the time from satellites, and the Sun and all the sources.  Just not x-rays and gammas, the atmosphere attenuates those too well.  But microwaves, IR, visible, UV are generally just distinctions of wavelengths that are arbitrary and defined by us humans.  The attenuation depends sharply on wavelength...visible is really better for penetration and beaming through the atmosphere.  As for design, you have to design the emitter for the wavelength...which also drastically affects how much surface area you'll hit.  A collmated laser will still hit a relatively large area due to hundreds of kilometers of diffraction and scattering.  Unless I have a more specific wavelength range, I can't be of more help than to offer you an estimate for the minimum area depending on your distance and your emitter: http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/raylei.html

(hyperphysics is a university-maintained and reliable resource for many such science questions)

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Dr. Stephen O. Nelson

Expertise

I can answer most basic physics questions, physics questions about science fiction and everyday observations of physics, etc. I'm also usually good for science fair advice (I'm the regional science fair director). I do not answer homework problems. I will occasionally point out where a homework solution went wrong, though. I'm usually good at explaining odd observations that seem counterintuitive, energy science, nuclear physics, nuclear astrophysics, and alternative theories of physics are my specialties.

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I was a physics professor at the University of Texas of the Permian Basin, research in nuclear technology and nuclear astrophysics. My travelling science show saw over 20,000 students of all ages. I taught physics, nuclear chemistry, radiation safety, vacuum technology, and answer tons of questions as I tour schools encouraging students to consider careers in science. I moved on to a non-academic job with more research just recently.

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Ph. D. from Duke University in physics, research in nuclear astrophysics reactions, gamma-ray astronomy technology, and advanced nuclear reactors.

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