SONIC BOOM

 

A sonic boom is the sound produced by an object that travels faster than the speed of sound in air.

The speed of sound varies depending on the temperature, pressure and humidity of the air, but it's roughly 767 mph at sea level.

When an object breaks the sound barrier, it creates a shock wave that radiates outward in a cone shape.

Anyone inside that cone will hear a loud boom as the shock wave passes by.

The answer to your question has many factors.

One of them is the altitude of the object.

The higher it goes, the thinner the air becomes, and the less energy the shock wave has.

That means the sonic boom gets weaker and narrower as the object ascends.

Another factor is the direction of travel.

If the object is moving away from us, the shock wave will be stretched out and lower in pitch, making it harder to hear.

If the object is moving toward us, the shock wave will be compressed and higher in pitch, making it louder and more noticeable.

Sometimes there are multiple booms.

This happens when a rocket has more than one stage or booster that separates during flight.

Each stage or booster can create its own sonic boom as it falls back to Earth, depending on its speed and trajectory.

SpaceX's Falcon 9 rocket has a reusable first stage that lands back at Cape Canaveral after launch, creating a triple sonic boom as it slows down and approaches the landing zone.

The second stage continues to orbit with the payload, creating another sonic boom as it reenters the atmosphere.

Timing is everything

A sonic boom from a launch will usually occur several minutes after liftoff, depending on how far away we are from the launch site and the flight path of the rocket.

Another clue is the weather.

A clear sky will allow the sound to travel farther and louder than a cloudy or rainy one.

And of course, another clue is the news.

If there's a scheduled launch from Cape Canaveral or another spaceport, chances are we'll hear about it before we hear it.