Important! NASA Huntsville Confirms Fireball Size ... Jackson, Miss 11JAN2011

Bright Fireball Flames in Southern Skies
Posted on Jan 13, 2011 10:55:43 AM by William Cooke, NASA 
Editor's Note: A rare snowstorm isn’t the only interesting thing that happened across the South this past week. On the night of Tuesday, Jan. 11, an extremely bright fireball meteor streaked over Jackson, Miss., and was visible across several southern states. NASA astronomer Bill Cooke of the Meteoroid Environment Office at Marshall Space Flight Center confirms the meteor below.

Okay folks, can confirm that this was indeed a fireball or bolide. Unfortunately no video of the actual meteor has surfaced, so I requested an analysis of signals from North American infrasound stations. We had one very clear detection, from the ELFO station in Canada, and a marginal signal at another station east of the visual sightings. Unfortunately the marginal signal is too weak to permit extraction of much information or to triangulate.

The ELFO signal arrived at 10:05:50 PM Central time, some 1 hour and 20 minutes after the event, and came in at an azimuth of 210 degrees. If you look at the attached plot, the black curved line shows the path of the ELFO signal, which intersects nicely with the bulk of the visual observations -- indicated by the red dot  -- around Jackson, Mississippi (ELFO az gives 32 deg N, 89 deg W -- Jackson is at 32 deg N, 90 deg W).

ELFO radio signal indicates 11JAN2011 meteor over Jackson, Mississippi
(c) NASA 2011

The infrasound signal at ELFO lasted some 2.5 minutes, and the amplitude permits an estimate of the meteor's energy at 4.6 tons of TNT. If we assume a speed of 15 kilometers per second, we can derive a mass of 171 kg or 376 pounds. Making a further assumption that the meteor was porous rock gives a size, or diameter, of 0.54 meters or 21 inches.