People from Cullman County to the Birmingham metro area heard a window-rattling blast Tuesday afternoon sometime around 1:45 PM. So what was it?
Our friend Dr. Bill Cooke at the Meteoroid Environment Office (NASA) here in Huntsville has been looking into it, and Molly Porter from his office tells us this tonight:
The origin of that mysterious boom that rocked central Alabama today remains unclear. Here’s what we know right now:
• Seismic data from the U.S. Geological Survey’s Lakeview Retreat near Centreville, Alabama, show a fairly loud boom occurring on or before 1:39 p.m. CST.
• The Elginfield Infrasound Array located in southern Ontario, 600 miles from north Alabama, picked up a matching infrasound signal beginning at 2:02 p.m. and lasting around ten minutes. The signal could have been generated by a bolide, large supersonic aircraft or a ground explosion.
• Eyewitness reports of a vapor trail point to a meteor or an aircraft as a possible cause.
The sound was not caused by a Leonid meteor, which is the light produced by a fragile bit of comet hitting the atmosphere at over 150,000 miles per hour. At such speeds, the particle does not last long, burning up completely at altitudes of 60 miles or so. Leonids never penetrate low enough into Earth’s atmosphere to produce sounds audible on the ground.
As new data become available (perhaps mid-morning tomorrow), our meteor scientists and their colleagues will do further analysis to triangulate and better characterize the energy of the event, which may provide more clues.