超级大火球

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SUPER-BOLIDE: On Wednesday, July 25th at approximately 10:00 UT, "a major daylight fireball tore across the skies of Slovenia, Croatia and Italy," reports veteran meteor observer Jure Atanackov of Maribor, Slovenia. "It produced two bright flashes that reached an estimated magnitude of -20 and also loud sonic booms."
Magnitude -20? In plain language, the meteor was 600 times brighter than a full Moon. Atanackov has gathered reports from hundreds of eyewitnesses. "Most described the fireball as very bright, its surface brightness almost as great as the Sun's. One person said it was 'too bright to look at for more than a few moments.'"
The July 25th fireball falls into the category of superbolides--exploding meteors of magnitude -17 or brighter. They are, essentially, small asteroids measuring a few to 10 meters in diameter and massing a few hundred metric tons. Superbolides trigger seismic detectors on the ground, produce waves of infrasound that can travel thousands of miles, and they are tracked by military satellites scanning Earth for nuclear explosions. Recent examples include the El Paso fireball of 1997 and the Yukon fireball of 2000.
Eyewitnesses, please report your sightings to Jure Atanackov or colleague Javor Kac who are gathering data to learn more about the "Slovenian Superbolide" and to estimate possible landing sites.