Through which process does energy primarily leave the planet Earth?

Energy primarily leaves the planet Earth through radiation. This process occurs when energy, particularly in the form of infrared radiation, is emitted from the Earth's surface into space. The Earth receives energy from the Sun, which is primarily in the form of visible light and ultraviolet radiation. After this energy is absorbed by the Earth's surface, it is re-radiated as infrared radiation, which has longer wavelengths and is less intense than the incoming solar energy.

In contrast, convection and conduction are processes that primarily involve energy transfer within the Earth's atmosphere and surface. Convection involves the movement of heat through fluids (like air or water) due to differences in temperature and density, while conduction refers to the direct transfer of heat through a solid material. These processes help distribute energy throughout the Earth system but do not account for energy leaving the planet.

Understanding the radiative process is critical, as it plays a significant role in the Earth's energy balance and climate system. The greenhouse effect, where certain gases in the atmosphere trap some of the outgoing infrared radiation, further illustrates the importance of radiation in the context of Earth's energy dynamics.