- A sonic boom is the loud noise that results when something breaks the sound barrier.
- You break the barrier by traveling faster than the speed of sound, which is 768 mph at sea level.
An F-16 scrambled to intercept a nonresponsive plane on Sunday, and the fighter jet caused a sonic boom heard in the DC area.
A sonic boom is a loud noise that people on the ground can hear when an aircraft, for example, breaks the sound barrier by traveling faster than the speed of sound.
Supersonic flight is banned over land in the US without special government authorization because of the inconvenient noises and tremors it can produce.
Here's what happens when a plane breaks the sound barrier:
When a plane goes fast enough, it compresses the air it's flying through so much that it can change its density, creating shock waves in the shape of a cone.
These shock waves act just like the wake behind a boat, which happens because it disrupts the water by moving faster than the water waves were moving.
Air pressure right at the tip of the cone in front of the plane is normal, while the pressure inside the cone is high because of the plane passing so quickly through it and pushing the atoms of air together.
Since the plane concentrates the sound wave energy into one place, you hear it all at once — producing a "boom" noise instead of the typical sound of a jet flying by.
NASA developed a way to see supersonic shock waves, and the images are gorgeous
NASA and the US Air Force have been trying to visualize this effect for years so they can build better supersonic aircraft and enable them to go faster than the speed of sound.
Until recently, these kinds of tests were contained to wind tunnels on the ground.
There, researchers used the Schlieren technique, invented by German physicist August Toepler in 1864, to understand more about how air travels around supersonic aircraft.
Schlieren imaging is a way to see the differences in air density, using a particular setup of lenses and cameras.
Decades later, NASA researchers have adapted this method to visualize supersonic aircraft in flight.
Bringing the Schlieren method into the air has been challenging because the aircraft carrying the imaging equipment has to fly right above the plane it's recording, and travel just as fast — which, during supersonic imaging, is faster than the speed of sound.
The T-38C, a supersonic US Air Force training jet that NASA imaged, traveled at a top speed of Mach 1.09 during the tests. (Mach 1 is the speed of sound, which is about 768 mph at sea level.)
But the tricky maneuvering was worth it for these gorgeous images, showing the shock wave of the T-38 flying over the Mojave Desert:
Here's another Schlieren image visualizing the supersonic flow of the T-38 jet in flight:
Understanding more about how supersonic aircraft affect the air around them could help develop ways to make planes quiet enough for commercial travel, opening the door to make the trip from New York to London a whole lot faster.