What Travels Faster: Light or Sound?

Light travels at a considerably higher speed than sound. Light travels at a constant speed of 186,000 miles per second, but the speed of sound is only 761.2 mph.

There are a number of differences between how sound and light travel. Light maintains a constant speed throughout the universe and is the fastest that anything can travel between two points. Meanwhile, sound relies on air pressure to transfer waves along its trajectory. This means that temperature and barometric pressure change the speed at which sound travels.

For example, sound moves much more slowly in cold air, because the gas molecules in the air move more slowly. Warming the air ensures that sound waves can move more quickly through it. Light has no such handicap and travels infinitely outward from its source at the same constant speed until it strikes a barrier. This is why the speed of light is used as a universal constant by many astronomers when calculating the distance to points relative to their location to the Earth.

Physics also co-opts the speed of light, using it to determine the potential energy of matter based on its mass. The first quantitative measurement of the speed of light took place in 1676, thanks to the calculations of Ole Roemer.