Sound is the the vibration of air molecules that propagate in a wave from a source. These are commonly known as “sound waves”. Sound waves can travel through air, water and even through solid objects. Sound however, cannot travel in a vacuum — such as space.

Sound cannot travel through space because there is no medium (air molecules) for sound to travel through. Since sound travels through things by vibration, the lack of molecules to keep the vibration chain going means that the sound waves cease to exist.

Imagine, for a moment, that you could somehow survive in space without a space suit. Now imagine that a roaring rocket or jet engine was firing 5 feet away from your head. That intense blast would be completely inaudible to you – you wouldn’t hear a thing. You would be able to feel the heat from the rocket engines because the photons (light) coming from the flames need no medium to travel, but you wouldn’t hear anything.

How Is Sound Measured?

Sound can be measured or identified in a few different ways. The most common methods are by either (or a combination of) frequency, amplitude, pressure level and decibels. The most commonly used measurement, and for our purpose of determining the loudest sounds, we’re going to focus on the decibel.

What Is A Decibel?

The decibel (dB) is a unit of measurement to gauge the intensity of a sound or noise. It’s a logarithmic unit which means that you cannot add and subtract dB like regular numbers. For example, an increase of 3 dB is a doubling of the “strength” or power of the sound, an increase of 10 dB means that the sound is 10x as loud; i.e., 70 dB is 10 times as loud as 60 dB. As you increase the numbers, the sound gets exponentially louder. This is similar to how the Richter scale works.

World’s Loudest Sound

So what’s the world’s loudest sound? The loudest sound currently on record is the Tunguska event which occurred in 1908, in Siberia. The event is believed to have been caused by the air burst of a small comet or asteroid which exploded roughly 3-5 miles above the earth. It exploded with an estimated force of 10-15 megatons of TNT, that’s 1000x more powerful than the nuclear bomb dropped on Nagasaki. Reportedly, the sound wave broke windows and knocked people off their feet hundreds of miles away.

Below, we’ve provided a helpful infographic with some interesting sound facts and statistics. It also provides some valuable information regarding hearing loss when exposed to certain dB levels. Don’t take your hearing health lightly.