E-M radiation and the atmosphere

• The atmosphere only passes certain ``spectral windows'' (either way).
• The atmosphere is transparent to visible light (why do you think our eyes evolved to be sensitive to these wavelengths?), some parts of the radio spectrum, and some parts of the Infrared.

  Fortunately, UV, X-ray and Gamma ray radiation does not reach the surface of the Earth as they all cause various bad things to happen to humans, other animals and plants. This also means if we want to make observations of X-rays from the Universe we need to launch X-ray observatories into space.