Breaking the sound barrier usually comes with a deafening bang, but a new experimental aircraft has done it silently—at least from the ground.
Boom Supersonic, an American aerospace company, recently announced that its XB-1 test jet successfully reached supersonic speeds in recent test flights without producing an audible sonic boom.
The Science Behind a Silent Supersonic Flight
When an aircraft moves through the atmosphere, it disrupts air pressure, generating sound waves. At speeds exceeding Mach 1 (approximately 1,224 km/h), these waves merge into shockwaves, creating the infamous sonic boom—a powerful blast that can rattle windows and even crack glass.
The disruptive noise was one of the key reasons why the Concorde, the world’s most famous commercial supersonic jet, was retired in 2003. Many countries banned supersonic flights over land due to the intense noise pollution they caused.
However, XB-1 has found a way around this problem using a phenomenon known as Mach cutoff.
At high altitudes, sound waves travel more slowly due to thinner air. If an aircraft reaches supersonic speeds at the right altitude, its sonic boom won’t reach the ground. Instead of traveling downward, the shockwaves bend upward, dispersing harmlessly into the sky.
According to Bernd Liebhardt from the German Aerospace Center, factors like temperature and wind speed also influence how sound waves behave. Engineers must precisely predict atmospheric conditions to ensure that Mach cutoff works as intended.
The Future of Supersonic Travel
Boom Supersonic’s latest test flight on February 10 confirmed that XB-1 can consistently break the sound barrier without a ground-level boom.
Now, the company is channeling these insights into its next project: Overture, a commercial supersonic passenger jet designed for transcontinental flights. Overture is expected to be 50% faster than current airliners, potentially cutting the New York to Los Angeles flight time by 90 minutes.
If Boom Supersonic succeeds, it could revolutionize air travel, bringing back supersonic flights in a way that’s quieter, more efficient, and passenger-friendly—without disturbing those on the ground.