The Experience of Hearing a Sonic Boom from High Altitude: A First-Hand Account

Have you ever heard a sonic boom from an aircraft at high altitude? It is a sharp, thunder-like noise that can be quite startling to those who experience it for the first time. This article explores the firsthand experience of a sonic boom from a supersonic aircraft, focusing on the details and sensations of the sound and its impact on the observer.

Overview of Sonic Booms

A sonic boom from an aircraft at high altitude sounds like a sharp, thunder-like noise when heard from the ground. This noise is generated when the aircraft exceeds the speed of sound, approximately 343 meters per second or 1125 feet per second at sea level. As the aircraft travels faster than the speed of sound, it generates shock waves that propagate outward, resulting in a sudden and powerful sound that can be described as a loud bang or clap, often compared to a small explosion or a thunderclap. The sound is transient, lasting only a fraction of a second, and it can produce vibrations felt on the ground or in nearby structures. The intensity of the sonic boom can vary depending on factors such as the altitude of the aircraft, its speed, and atmospheric conditions.

Firsthand Experience: The SR-71 Blackbird Incident

During the mid-1980s, a unique incident took place when a SR-71 from Beale AFB in California was tasked to fly across the country at supersonic speed to the search area for a lost boat in the Atlantic Ocean. Being an aerospace engineer in the USAF at the time, I was not initially aware of this mission. However, I was in our townhouse apartment in Ohio and noticed something unusual. As I was in the small basement, with a small window above ground level, I heard two distinct bangs, maybe a half-second apart. At first, I thought it was someone slamming doors upstairs, but the only people in the house were my family.

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The sound was very much like a rifle shot from maybe a hundred yards away, much like the sound I had heard before from a fighter jet at Edwards AFB. This time, however, it was surprising to hear two bangs in quick succession. A few days later, at work, I learned that an SR-71 had flown over at the time of the noise. As an aerospace engineer, I knew there were actually two main shocks from a supersonic airplane: one from the nose and the other from the tail. However, this was the first time I had heard both.

Comparing Sonic Booms from Different Aircraft

Later in my life, I lived about 20 miles west of the Shuttle Landing Facility in Florida, where I frequently heard the double boom as landing shuttles passed over. These booms were often much stronger than those heard from the SR-71. If the flight path was nearly overhead, the doors and windows would rattle. The booms were more akin to deep, powerful thuds than sharp cracks. After the second shock, if the path was close to the house, there was also a sort of white noise, like static or ripping paper, that took several seconds to fade. This noise was quieter than the boom itself, and it required being outside to hear it clearly.

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Impact of Sonic Booms

Interestingly, local hospitals used to report an increase in births nine months after night landings. While this may seem like a coincidence, it is not entirely surprising. The shock waves generated by the sonic boom can affect both human and animal physiology. The noise and vibrations can cause stress and disrupt the natural circadian rhythms of pregnant women, potentially leading to an earlier delivery.

Conclusion

The experience of hearing a sonic boom from an aircraft at high altitude can be both awe-inspiring and startling. It is a phenomenon caused by the supersonic speed of the aircraft and the resulting shock waves. Personal experiences with the SR-71 and the space shuttle further highlight the intensity and variability of these sonic booms. Whether from an SR-71 or a space shuttle, the boom is a testament to the power and allure of supersonic flight.