Radiant energy is a form of kinetic energy. It is the energy of electromagnetic waves that can travel through space.
The sun is a vast source of radiant energy on Earth. For example, plants absorb electromagnetic waves and, via photosynthesis, produce their food. When the sun's radiant energy touches our skin, the waves make our skin's molecules move faster, and we feel warmer.[17]
We can see radiant energy waves as light energy — the only form of energy the human eye can see. Radiant energy's magnetic waves can also be invisible, such as X-rays and radio waves.[18]