What’s the loudest sound you’ve ever heard? Many people will say an aircraft engine unless they are lucky enough to have attended a rocket launch. And if there was one rocket that was louder than them all, it was the Saturn V, the behemoth that blasted the Apollo astronauts to the moon. But just how loud was it?
To be precise, about 203 decibels. A standard aircraft engine on a commercial jet is around 150 decibels. While a 36% increase in noise over a typical jet engine might not sound like a significant difference, remember that decibels are mapped on a logarithmic scale. That means that every 10 dB is actually an order of magnitude more noise. So a 160 dB sound is ten times louder than a 150 dB sound.
By that math, a Saturn V blasting off is 10,000 louder than a standard commercial jet engine. That is some pretty serious acoustic power and has led to some myth-making on certain parts of the internet. Enough that scientists have directly addressed an education paper to it.
Internet legend says that the Saturn V was so loud its acoustic energy would liquify concrete and set nearby fields on fire. But those phenomena, if they did happen at all, are much more likely to be caused by the extraordinarily hot plume of fire coming out the back of the rocket engines than by anything acoustic.
But the thought of acoustic waves causing such devastation shows how little is understood about them. So a team of scientists decided to write a paper debunking these claims and estimating just how loud the Saturn V was as part of a special educational edition of the Journal of the Acoustical Society of America.
A team from Bringham Young University used some models of the physics of the Saturn V to try to estimate how loud it would be. The number they came up with, 203 dB, was very similar to the limited acoustic data collected in the 60s and 70s when the rocket was in regular use.
If their techniques interest you, or you just miss the days of being able to do physics homework problems in school, the paper also contains some homework problems that could be useful in college classrooms. It might even help you calculate the decibel levels of what might be another thunderous rocket engine.
The Space Launch System, when it launches, will be the first rocket more powerful than the Saturn V. Technology has improved immensely in the last 60 years, so there is no guarantee that the SLS will be in the same acoustic range as the Saturn V. Starship, which is said to be even more powerful, would offer another chance to test your acoustical modeling skills, or just experience a deep guttural vibration if you’re able to witness it.
Both launches are undoubtedly targets for an array of acoustic collection technology this time around. But even with all the data in the world, it will likely be impossible to stop the internet from coming up with tall tales regarding the power of this new class of massive rockets. While the stories that come from it might be amusing, please be sure not to believe everything you read on the internet.
Launch image of a Saturn V.
Credit – NASA