We sometimes hear terms like “supersonic” and “sonic boom” in our daily lives, but they’re often associated with product marketing or grandiose description rather than the actual phenomenon caused by breaking the so-called sound barrier.
If you’ve ever wondered what exactly a sonic boom is, read on for a clear and concise answer.
What is a Sonic Boom?
When an object moves through the air, whether it’s you out for a stroll or a passenger plane soaring through the sky, it pushes air ahead of it in waves, similar to those produced in water at a ship’s passing. When such an object moves faster than the speed of sound – about 1,200 kilometers (750 miles) per hour at normal atmospheric pressure at sea level – the pressure waves that it is pushing ahead of itself necessarily compact ahead of it, producing shock waves which then begin to travel behind it.
As these shock waves release their pressure, the effect reaches our ears and is interpreted as the booming of rushing, condensed air – a sonic boom. As the object continues to fly through the atmosphere at speeds exceeding that of sound, it will continue to leave shock waves, and thus sonic booms, in its path.
What Does a Sonic Boom Look Like?
As you can see in the photograph above, there is also a visual phenomenon associated with a sonic boom. Appearing as a vertical, flattened cloud, this extraordinary sight appears courtesy of water vapor, but the “why” of the cloud is the more interesting topic.
While theories abound, the one most accepted postulates that, when a plane reaches supersonic speed, the sudden drop in air pressure associated with the crunching of sound waves causes the surrounding atmospheric moisture to suddenly condense into water droplets, forming a strange portal-like cloud around the plane itself.