Final answer:
The sun's energy that reaches Earth is categorized in the electromagnetic spectrum, organized by frequency and wavelength. The only part visible to humans is called visible light, which includes the colors of the rainbow.
Step-by-step explanation:
The sun's energy comes to earth as waves of radiant energy. This energy is part of the electromagnetic spectrum, which includes all forms of electromagnetic radiation ranging from gamma rays to long radio waves, each with its own wavelength and energy. Within this spectrum, the visible light is the portion that the human eye can detect, comprised of the colors of the rainbow from red to violet. When these colors combine, they create what we perceive as white light. Therefore, the sun's radiant energy is placed into a chart called the electromagnetic spectrum. The different forms of energy are organized based on the frequency and wavelength of the waves. The only portion of the spectrum that can be seen by the human eye is called visible light.