Final answer:
The Earth emits energy primarily as thermal infrared radiation, with different regions of the electromagnetic spectrum characterized by varying wavelengths and energies. Radio waves are at the lowest energy end while gamma rays hold the most energy per photon.
Step-by-step explanation:
The question involves understanding the type of electromagnetic radiation that the Earth predominantly emits. The Earth radiates energy into space primarily in the form of thermal infrared radiation. This is because the Earth's surface and atmosphere are at temperatures that, according to Wien's law, emit radiation peaking in the infrared segment of the spectrum. Visible light is not the dominant wavelength emitted by the Earth, as the temperature of the Earth's surface is not high enough to emit energy at such short wavelengths.
The different regions of the electromagnetic spectrum are characterized by their wavelengths and the amount of energy they carry. The list in ascending order of photon energy is: radio, microwave, infrared, visible, ultraviolet, X-ray, and gamma radiation. This means that short-wavelength gamma radiation carries the most energy per photon, whereas long-wavelength radio radiation carries the least.