How does our atmosphere block infrared radiation from space?
Only certain parts of the electromagnetic spectrum (all light ranging from gamma ray to radio waves) can make it to the Earth’s surface. Much is absorbed by our atmosphere. Visible light, radio waves and a few small ranges of infrared wavelengths do make it through. Gamma rays, and most of the ultraviolet rays and infrared rays do not. Much of the infrared light is absorbed by water vapor in our atmosphere. This is why infrared telescopes are placed on high, dry mountains (like Mauna Kea in Hawaii) so that they can observe more infrared radiation. The only way to study the entire range of infrared (as well as gamma rays, xrays, UV) is to place telescopes in space well above the atmosphere. Only some (not all) of the IR radiation between 1 and 40 microns makes it to the Earth’s surface. The rest is absorbed by our atmosphere primarily by water vapor. IR is also absorbed to a lesser degree by carbon dioxide and oxygen molecules.
