Hacker News Reader

So if, in the future, this material was in heavy use atop buildings and dwellings across the planet, and the heat is all being radiated out the same thermal window, does this mean that at some set distance from the earth, there's a ring of extreme heat being generated?

View on HN

> a ring

Well, a sphere of expanding energy, anyway. Just like the shell of TV broadcast energy that leaves the planet. Also, we rotate and move in space, so less of a sphere and more like a windy tube.

I'm probably missing something in the definition of "thermal window".

The thermal windows refers to the fact the earth's atmosphere is pretty good at letting through longer wavelength IR than shorter wavelength IR.

http://en.wikipedia.org/wiki/File:Atmosfaerisk_spredning.png

As an example. Visible light is that little bit all the way to the left. That entire big chunk on the right is the thermal window that they're talking about.

Reply on news.ycombinator.com