You're responding to a point I wasn't making. I was talking about the space heater laser comparison. The comparison was a conservation of energy comparison. Let me say it again: The heat energy dissipated by a laser traveling through 5 miles of atmosphere is almost certainly greater than the heat energy generated by a space heater. Even if you adjust the power levels and exposure times, I don't see it. As for the point you DID make, that was brought up by a different poster and yes, I can see that. You're basically saying that the laser energy and energy loss relation is not linear.
"The heat energy dissipated by a laser traveling through 5 miles of atmosphere is almost certainly greater than the heat energy generated by a space heater."
How does one respond to this? It doesn't make much sense.
A 50 watt laser with a 0.08" diameter beam has a power density of 50 watts over a 0.005 square inch area.
For your space heater with a 24" by 12" face to have the same power density it would have to emit 2.86 million watts of heat...
The laser produces mostly coherent light meaning the beam does not spread much over distance. Therefore the energy density remains high over long distances.
Your space heater generates random wave length infrared light and it spreads out over distance. As it spreads the power density drops with the square of the distance as it fills more and more area. In other words the space heater's power density drops by a factor of 4 for every doubling of distance.
Most of the energy loss (to the intended target) through the atmosphere is by it being scattered, not absorbed for the laser. Even this is pretty low under clear sky conditions. These loses are constant as percentage of loss until you get to very high energy levels. Far, far beyond a 50 watt laser.
The atmoshpere reflects/aborbs only about 50% of the sun's energy passing through it. That is more than 20 miles of atmosphere. Absortion accounts for 19% of that loss. The power density of solar radiation from the sun at sea level is about 440 mW per square inch. Or about 2.2 mW over the same area as the laser. Therefore the 50 watt laser light is about 22,727 times more intense than the sun at sea level over the area of the laser beam dot. Severe eye damage occurs very quickly.