Crater mystery of melted rocks.

• Position: Meteorites - Brief Article

The iron meteorite that blasted out Meteor Crater almost 50,000 years ago was traveling much slower than has been assumed, hypothesizes Gareth Collins of the Imperial College of London. The meteorite smashed into the Colorado Plateau in Arizona 40 miles east of where Flagstaff and 20 miles west of where Winslow have since been built, excavating a pit 570 feet deep and 4,100 feet across---enough room for 20 football fields.

Previous research supposed that the meteorite hit the surface at a velocity between about 34,000-44,000 mph. Collins used sophisticated mathematical models in analyzing how the meteorite would have broken up and decelerated as it plummeted down through the atmosphere. About half of the original 300,000-ton, 130-foot-diameter space rock would have fractured into pieces before it hit the ground. The other half would have remained intact and hit at about 26,800 mph.

That velocity is almost four times faster than NASA's experimental X-43A scramjet--the fastest aircraft flown--and 10...