Here's why:

* Light: Travels at the speed of light, which is approximately 299,792,458 meters per second (186,282 miles per second) in a vacuum. This is the fastest speed anything can travel in the universe.

* Sound: Travels as vibrations through a medium (like air, water, or solids). The speed of sound depends on the medium, but it's significantly slower than the speed of light. For example, in air at room temperature, sound travels at about 343 meters per second (767 miles per hour).

That's why you see lightning before you hear thunder! The light from the lightning bolt reaches your eyes almost instantly, while the sound of the thunder takes time to travel through the air.