Light travels through space in the form of electromagnetic waves. Electromagnetic waves are composed of electric and magnetic fields that oscillate and propagate through space. When an electrically charged particle accelerates, it generates these oscillating fields, which then propagate outward in the form of electromagnetic waves.
In the case of light, the acceleration of charged particles occurs within atoms or molecules. When an atom or molecule undergoes a transition from a higher energy state to a lower energy state, such as when an electron moves from an excited state to a ground state, it releases energy in the form of electromagnetic radiation. This radiation consists of photons, which are packets of energy that behave both as particles and waves.
Once generated, photons travel through space in straight lines at a constant speed, which is approximately 299,792,458 meters per second in a vacuum (often rounded to 300,000 kilometers per second for simplicity). This speed is known as the speed of light and is one of the fundamental constants of the universe.
Unlike sound waves, which require a medium (such as air or water) to propagate, light does not require a material medium. It can travel through the vacuum of space as well as through transparent materials like air, water, and glass. This is because electromagnetic waves are self-propagating and can exist independently of a physical medium.
In summary, light travels through space as electromagnetic waves, which are composed of oscillating electric and magnetic fields. These waves propagate in straight lines at the speed of light, and they can travel through vacuum as well as transparent materials.