title: Planetary science: Meteor Crater formed by low-velocity impact.
abstract: Meteor Crater in Arizona was the first terrestrial structure to be widely recognized as a meteorite impact scar and has probably been more intensively studied than any other impact crater on Earth. We have discovered something surprising about its mode of formation--namely that the surface-impact velocity of the iron meteorite that created Meteor Crater was only about 12 km s(-1). This is close to the 9.4 km s(-1) minimum originally proposed but far short of the 15-20 km s(-1) that has been widely assumed--a realization that clears up a long-standing puzzle about why the crater does not contain large volumes of rock melted by the impact.
authors.affiliation: Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona 85721, USA. jmelosh@lpl.arizona.edu
authors.forename: H J
authors.initials: HJ
authors.lastname: Melosh
authors.forename: G S
authors.initials: GS
authors.lastname: Collins