What is a sonic boom, I’ve heard many people use it but I don’t know what it is
In: Physics
Imagine you’re playing with a toy plane really fast. When it goes faster than sound, it makes a big noise, like a clap. That loud noise is called a sonic boom! It happens when things move faster than sound can catch up.
Sound waves that should’ve dispersed around the aircraft become combined in front of the aircraft, causing da boom.
An object moves through air at a speed so high that the air itself cannot slide out of the path of the object. As this air piles up it compresses more and more, increasing in pressure quickly, and forming a shock-wave of air to all sides of the object in a cone. The air being so compressed holds itself in a cone, losing energy gradually. As the highly compressed air passes over a point the pressure spikes UP and then back DOWN to ambient in very little time, and that spike is experienced as a BOOM.
As you push through the air you create waves, the same way a boat creates waves on water. The speed those waves travel at is a relatively constant number (though it shifts slightly with air pressure, temperature, etc.) These waves we typically hear as that *whoosh* sound that things make as they fly by us at high speed. If you go faster than these waves travel you can create waves faster than the air can get out of the way so the waves build on top of each other. The peak of these combined waves is so great that the *whoosh* becomes a solid *pop* the larger the object the louder the *pop*. A whip creates a little crack as it’s tip goes faster than the speed of sound. A bullet creates a larger pop as it goes faster than the speed of sound. A jet creates a boom.
Imagine a pond (or puddle). If you drop something into it, you get ripples. This is kind of how sound works in air when you make a single loud noise; it makes a wave that bounces around.
Now instead of dropping a single object, imagine a boat floating in the pond. It keeps bobbing on the surface, so it keeps making ripples. This is how something that continues to make noise works in air; a bunch of ripples bounce around and interacts with the other ripples.
Now instead of standing still, the boat is moving across the pond. Each time it moves it creates a new ripple in its new position. If the boat moves slower than the ripples, you get a pattern of ripples where some are closer together near where the boat is moving towards, and farther apart where the boat is moving away from. This is how subsonic Doppler effects work, such as a siren sounding higher pitched when driving towards you than when it is driving away of you.
Now, instead of moving slower than the ripples, the boat is moving faster than the ripples are. Each new ring of a ripple is outside of the previous ones. But this means that there will come a line to the side of the boats movement where all the ripples will hit at the same time; this is how a boat’s wake happens, and why faster boats will have a wake that is bigger and more disruptive (more ripples hitting at the same time). This is how a sonic boom works; it’s basically a bunch of sound waves hitting things at the same time, like a boats wake but through the air.
When the X-59 was recently unveiled, one of the speakers made a really good analogy.
Imagine a large man belly flopping into a pool. The water cannot get out of the way fast enough. The faster the man travels, the harder it is for the water to get out of the way. The harder it is for the water to move, the louder the sound.
That plane is a work of art and engineering. Supersonic speeds with almost no boom.
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