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I'm very interested in knowing about how much energy would be lost to the atmosphere if you fired a laser or maser into space. I know the laser would probably diverge quite a bit over that distance, and the photons would probably lose a lot of their energy traveling through the medium of air. Just to be specific let's say the boundary to space is the Karman Line in this case (100km). The difference between a laser and maser is also important because of the absorption spectrum of the atmosphere.

The reason I'm curious about this is if you fired a powerful array of lasers or masers into the atmosphere powered by the heat in the atmosphere I'm curious how difficult it would be to provide a significant alteration to the effects of global warming, by moving excess energy into space.

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  • $\begingroup$ Google "absorption spectrum of the atmosphere" and you'll get dozens of references that can answer this question. $\endgroup$
    – The Photon
    Commented May 17, 2020 at 3:43
  • $\begingroup$ The answer to your final question woudl be "extraordinary difficult to a level you may not appreciate." The energy balances of a planet are massive. From one of my favorite pages on Wikipedia the energy of the sun striking the earth every day is something like 500x the total electricity use of the entire world for a year. Power on a planetary level is a thing to behold! $\endgroup$
    – Cort Ammon
    Commented May 17, 2020 at 5:49

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The extinction in the atmosphere is a function of atmospheric conditions, dust and aerosol concentrations, the angle to the vertical the laser is fired at, and of course the wavelength.

A typical value at 589 mm (sodium laser) in a clean atmosphere and a vertical beam would be about a 15% attenuation. It could easily be a factor of a few worse in more polluted atmosphere.

For a maser it would depend on the exact microwave wavelength and would also depend a lot on the water vapour content in the atmosphere.

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  • $\begingroup$ Lets say for example that we were placing the masers on Mauna Kea a hotspot for astronomy, which you probably know a lot about, I don't know what the humidity measurements listed here: agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2007GL031330 mean in terms of the water vapour content, but how would they affect a proposed maser? And can we pack a higher energy density into a certain square footage with modern lasers or masers? $\endgroup$
    – Ethan
    Commented May 18, 2020 at 2:11
  • $\begingroup$ Also how does the laser's attenuation relate to its energy loss over distance? $\endgroup$
    – Ethan
    Commented May 26, 2020 at 2:53

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