If you were one of the people that witnessed these sightings over the last week please reply to this post with the location from which this occurred.
Concerning tonight's fireball seen over much of the southern U.S... this is from Bill Cooke of NASA's Marshall Space Flight Center in Huntsville...
"Definitely a fireball; time was Dec 18 at 02:20:40 UTC or Dec 17 at 8:20:40 PM CST. It started out 52 miles above I-24 just south of Manchester, Tennessee and moved to the north of west at 50,000 mph. We lost track of it at an altitude of 23 miles just to the northwest of Shelbyville, Tennessee.
The closest camera (Tullahoma) shows that the fireball was about as bright as the Full Moon, which means we are dealing with an object about 20 inches across and weighing approximately 400 lbs. Orbit indicates this object is a piece of an asteroid, with an aphelion in the main asteroid belt between Mars and Jupiter, and perihelion (closest point to the Sun) inside the orbit of Venus."