Have you ever noticed that during a thunderstorm, you always see the lightning before you hear the thunder? This isn't just a trick of the mind; it's due to a fundamental difference in the speeds at which light and sound travel. Light, in the form of electromagnetic radiation, travels through the atmosphere at an astonishing 670 million miles per hour (1,080 million kilometers per hour). Sound, on the other hand, travels much slower, at a mere 767 miles per hour (1,234 kilometers per hour).