Ray, as of sunlight, can be described as a BEAM of light. Sunlight is composed of many different types of electromagnetic radiation, including visible light, which is what we see as rays of sunlight. Rays of sunlight are made up of photons, which are particles of light that travel in straight lines. Rays of sunlight are responsible for providing us with warmth and energy, and they are also essential for photosynthesis, which is the process by which plants convert light into energy.