Light travels at approximately 299,792 km/s, while sound moves at about 343 m/s in air, making light vastly faster.
Because of this huge difference in speed, we often see things before we hear them. For example, during a thunderstorm, you see a flash of lightning first, and then a few seconds later, you hear the thunder. This happens because light reaches your eyes almost instantly, while sound takes time to travel through the air.
Light doesn’t need air or any other material to move—it can travel through the empty space of the universe. That’s why we can see the light from the Sun and distant stars. On the other hand, sound needs something to pass through, like air, water, or solid objects. Sound cannot travel at all in space, where there is no air.
This speed difference is also why communication systems use light signals, such as fiber optics, to send information quickly. Sound-based communication, like talking or radio waves, moves much slower by comparison. Light always wins the race, whether it’s the flash of fireworks before the boom or the distant sight of an explosion before the blast reaches our ears.
