© University of Wisconsin - AOS/SSECThe meteor was bright green at first, and the sky was almost blue for a few seconds. The meteor then broke into several pieces and glowed orange as it faded away. Was visible for 10-15 seconds. The loop shows a plane going by, then the fireball that illuminates the contrail of that plane (and another from a previous plane that is not visible) The pictures were taken at 10PM CDT on April 14, 2010 (03 UTC April 15, 2010)
Last night, around 10:05 pm CDT, sky watchers in Minnesota, Wisconsin, Iowa, Illinois and Missouri witnessed a brilliant green fireball streaking across the sky. Images from a rooftop webcam in Madison, Wisconsin, show a brilliant midair explosion.

The fireball was caused by a small asteroid hitting Earth's atmosphere at a shallow angle. Preliminary infrasound measurements place the energy of the blast at 20 tons of TNT (0.02 kton), with considerable uncertainty. Bill Cooke of NASA's Meteoroid Environment Office estimates that the space rock was about 1 meter wide and massed some 1260 kg. "Fireballs of this size are surprisingly common," he notes. "They hit Earth about 14 times a month, on average, although most go unnoticed because they appear during the day or over unpopulated areas."

Many readers have asked if fragments of the meteoroid might have reached Earth. The answer is yes. Cooke advises looking directly underneath the fireball's debris trail, which was pinged by National Weather Service radars in Iowa. Click here and here for maps.
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