For example, oxygen and nitrogen absorb energy that has tightly packed wavelengths of around 200 nanometers or less, whereas infrared energy travels at wider and lazier wavelengths of 700 to 1,000,000 nanometers. That’s because molecules are picky about the range of wavelengths that they interact with, Smerdon explained.
Oxygen and nitrogen don’t interfere with infrared waves in the atmosphere. (Hold your hand over a dark rock on a warm sunny day and you can feel this phenomenon for yourself.) These infrared waves travel up into the atmosphere and will escape back into space if unimpeded. When sunlight reaches Earth, the surface absorbs some of the light’s energy and reradiates it as infrared waves, which we feel as heat. Credit: A loose necktie on Wikimedia Commons Greenhouse gases like carbon dioxide and methane absorb the infrared energy, re-emitting some of it back toward Earth and some of it out into space. Simplified diagram showing how Earth transforms sunlight into infrared energy.