Greetings, Is there a difference between reflection of radiation and emission after absorption? What causes this difference? Another related question: According to wikipedia: "Earth's surface and the clouds absorb visible and invisible radiation from the sun and re-emit much of the energy as infrared back to atmosphere" (source: https://en.wikipedia.org/wiki/Infrared#Earth_as_an_infrared_emitter) Does the earth actually emit some of the absorbed visible sunlight as infrared, or is it only infrared part of solar radiation that it simply emits back as infrared? What causes any object to emit radiation at a different frequency than the frequency it absorbed? Thank you for reading!