Unlike convection, radiation does not require any fluids in order to transport heat. The energy from the sun is one great example of radiation. The sun emits light in a broad range of wavelengths which all contain energy. These waves are also discussed in the climate section for energy balance. The waves are emitted from the sun and travel through space and hit the earth and other planets. Once the light waves hit the atmosphere and ground, the energy stored in the waves heats up the soil and air, allowing conduction and convection to occur and move energy around the earth/atmosphere system. [Note that this radiation is not the same as nuclear radioactivity, which is caused by transformation of atoms undergoing physical changes within naturally occurring rocks as well as nuclear power plants and bombs.]