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What Causes The Sonic Boom When An Aircraft Breaks The Sound Barrier?

We are all familiar with sonic boom; you know, the shock waves created when an object is travelling faster than the speed of sound. But have you ever wondered how is that massive sound energy generated? Why it can be heard as a big explosion to those on the ground? Well, wonder no more because we got you covered.

But before we get into it, we need to talk a bit about sound as a wave.

You see, sound travels in waves which, at sea level and at atmospheric condition of 72°F (22°C), has a speed of 770mph (345m per second). As the temperature decreases, the sound speed will also decrease and vice versa. Now, because the propagation of sound waves have limits, some sources of sound can catch up with the sound waves they produce. So, what happens when an object, a jet for example, breaks the sound barrier? (the article continues after the ad)

As the jet reaches the velocity of the sound waves, the sound waves begin to pile up in front of the plane. When the plane has sufficient acceleration, it bursts through the ‘barrier’ of sound waves and therefore, moves faster than the sound (an observer from the ground will first see the plane and then hear its sound). This causes a change in pressure and as the object breaks through that pressure, the sound waves in front can be heard on the ground as an explosion, the famous sonic boom.

If you like what you read, then you will definitely love this one: Why Does A Bad Apple Spoil The Bunch? 

Photo: skeeze / Pixabay
Photoshop: I’m A Useless Info Junkie
Sources: What happens when an aircraft breaks the sound barrier?

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