To retain (sunlight or sound, for example) wholly, without reflection or transmission. To transfer energy from light to matter. Photons can be absorbed by electrons in matter then emitted as visible light photons (this is reflection) or re-radiated as infrared photons (heat). A photon has energy and momentum, but no rest mass. If a photon comes to rest by being absorbed, it ceases to exist. Its energy has been converted to some other form of energy. When an object absorbs all light, we see black. When sunlight is absorbed by the ground, it feels warm. When light energy is absorbed by an object, the object might feel warmer because light energy is transformed to heat energy. See transform.