On Tuesday, the quiet scenery of Northern Alabama was rocked by a thunderous boom from the sky – which in and of itself may not be all that unusual, except there were no storm clouds, and no military aircraft were reported in the area.

At around 1:39 pm local time, the sound, which the Birmingham National Weather Service has hypothesized was likely a sonic boom, could be heard for hundreds of miles.  The NWS took to Twitter almost immediately, admitting to concerned residents that they “don’t have an answer, and can only hypothesize with you” about what it may have been.

If it wasn’t an aircraft, the NWS postulated, the next most likely candidate would have to be a meteor.  Military aircraft have strict regulations on when and where they are permitted to enter supersonic speeds when flying over inhabited stretches of American soil, and no civilian aircraft since the Concorde has been capable of breaking the sound barrier.  Further, the Leonid Meteor Shower is expected to reach its peak around November 17th or 18th, so Occam’s Razor would seem to dictate that it had to have been an early meteor, streaking across the Alabama sky at supersonic speeds.  Mystery solved, right?  Well, maybe not.

Bill Cooke, the head of NASA’s Meteoroid Environment Office (MEO) at the Marshall Space Flight Center in Huntsville, Alabama, is perhaps the man most qualified to determine if what’s been dubbed “the ‘Bama boom” was actually the product of a stray meteor swinging through early to announce the Leonid Meteor shower’s arrival.  According to him, the boom was not a meteor.  He instead posits that it may have been caused by the aforementioned supersonic aircraft possibility, a large ground explosion, or potentially a bolide – which is a large meteor that explodes in the upper atmosphere, but not tied to the forthcoming meteor shower.

Seismic data from U.S. Geological Survey’s Lakeview Retreat near Centreville, Alabama suggests that the boom was not caused by an earthquake, and similarly, a massive ground explosion would likely have registered as such on their instruments.  Between NASA and the U.S. Geological Survey, then, it would seem most likely that the boom was indeed caused by a supersonic aircraft… begging the question, who did the aircraft belong to?

Thus far, the U.S. military has not taken responsibility for the “’Bama Boom,” but there are a number of military duty stations in the region that could be linked to the event.  Maxwell Air Force Base in Alabama, for instance, houses training colleges such as the Air Force Officer Training School and Air Force ROTC, as well as the 908th airlift wing.  However, the base primarily sees C-130 flights, which are subsonic aircraft incapable of producing such a sonic boom.  Robbins Air Force Base in nearby Georgia houses a fleet of F-15 Eagles, which could potentially be the culprit, but thus far, they have not taken responsibility for the thunderous sound.

NASA or the Air Force may soon make a statement shedding some light on the mysterious noise heard throughout at least eleven counties in Alabama on Tuesday – either by claiming responsibility for it or identifying it as a bolide.  Until then, however, residents of Alabama continue to look up to the sky with a sense of confusion, wondering just what could have been that was heard for hundreds of miles around.