The Earth's atmosphere is important because the Atmosphere reacts, protects, and transports. Imagine a world where the daytime sky was not blue, but black. Imagine the Earth without clouds, wind, or rain. Imagine for a moment having to walk outside of your house in a space suit, just like an astronaut on the Moon! Our atmosphere is more than just hot (or cold) air. Without our atmosphere, the surface of the Earth would be subject to the harsh radiation coming from the sun. All living beings on Earth depend on the atmosphere for protection from the sun's harmful rays. In the upper reaches of the atmosphere, atoms of gas react with some of the high-energy radiation coming from the sun. These reactions absorb some of the sun's energy and prevent it from reaching the surface of the Earth where it is harmful to life. Throughout the atmosphere, winds transport clouds, precipitation, and particles across the globe. It is because of the atmosphere that heat is transferred from the equator to the mid latitudes and the Earth's poles.