Final answer:
Radiation emitted from Earth's surface primarily falls within the infrared portion of the electromagnetic spectrum, which has lower energy compared to visible and ultraviolet light.
Step-by-step explanation:
Radiation emitted from Earth's surface is concentrated in the infrared portion of the electromagnetic spectrum. Infrared radiation is the region of the electromagnetic spectrum characterized by wavelengths longer than those of visible light but shorter than those of microwave radiation. The energy of infrared radiation is lower than that of visible light and much lower than that of ultraviolet light, which is known to be harmful to living tissues.
The Earth emits thermal radiation that falls primarily within the infrared region because the surface of the Earth is much cooler than the Sun. This difference in temperature between the Earth and the Sun leads to the Sun emitting radiation that is primarily in the form of visible light and ultraviolet radiation, which have much higher energies than the Earth's infrared radiation.