Mystery of Arizona ' s Meteor Crater Solved By Robert Roy BrittSenior Science Writerposted : 09 March , 20051 : 00 p . m . ETThe space rock that carved Meteor Crater in Arizona hit the planet much more slowly than astronomers once figured , but still 10 times faster than a rifle bullet . 최근 아리조나 크레이터 의 충 돌체 가 생각 보다 느린 속도 로 충돌 했 다는 연구 결과 The new analysis , announced today , explains why there ' s a lot less melted rock in the crater than expected . The mystery has dogged researchers for years . The big hole in the ground -- 570 feet deep and 4 , 100 feet ( 1 . 25 kilometers ) across -- was blown into existence 50 , 000 years ago by an asteroid roughly 130 feet ( 40 meters ) wide . Previous calculations had the rock slamming into the ground at no less than 34 , 000 mph ( 15 km / sec ) , based in part on the expected speeds of large meteors in relation to Earth . Such an impact ought to have generated more melted rock in and around the crater than what ' s been found . 과거 에 충돌 속도 는 초속 15 킬로 추정 그러나 예 상외 로 녹아내린 암석 이 적 어 A new computer model , reported in the March 10 issue of the journal Nature , shows the incoming object would have slowed considerably during its plunge through the atmosphere , part of it breaking into a pancake - shaped cloud of iron fragments prior to impact . About half the original 300 , 000 - ton bulk remained intact , smacking the planet at about 26 , 800 mph ( 12 km / sec ) , said the study ' s lead researcher , Jay Melosh of the University of Arizona . 최근 연구 에 의하 면 초속 c 12 킬로 미터 로 충돌 Meteor Crater , a popular tourist destination , was the first scar on Earth confirmed to have been gouged by a rocky visitor from beyond . " It ' s probably the most studied impact crater on Earth , " Melosh said . " We were astonished to discover something entirely unexpected about how it formed . " The modeling is based in part on investigations decades ago by Daniel Barringer , whose name is officially associated with the crater . Barringer and others found chunks of the iron space rock weighing from a pound up to 1 , 000 pounds in a 6 - mile - diameter circle around the crater . The new work also draws from an improved understanding of how Earth ' s atmosphere cushions extraterrestrial blows . In 1908 , a good - sized asteroid -- more stony in nature -- exploded above the surface of Siberia , flatting hundreds of miles of forest but leaving almost no extraterrestrial trace . During the satellite era , scientists have monitored car - sized space rocks routinely exploding in the air . " Earth ' s atmosphere is an effective but selective screen that prevents smaller meteoroids from hitting Earth ' s surface , " Melosh explained . The effect of screaming through the air , even for an iron - heavy meteorite like the one that struck Arizona , is a lot like hitting a wall , Melosh said . And many space rocks are already cracked before they arrive , scientists believe . " Even though iron is very strong , the meteorite had probably been cracked from collisions in space , " Melosh said . " The weakened pieces began to come apart and shower down from about 8 . 5 miles ( 14 kilometers ) high . And as they came apart , atmospheric drag slowed them down , increasing the forces that crushed them so that they crumbled and slowed more . " The results evolved out of a project in which Melosh and colleagues developed a " Catastrophe Calculator " that predicts the effects of asteroids of varying size and composition striking any given location on the planet .