Exam 12: Impact of Extraterrestrial Objects

Why are impact craters more common on the Moon and Mars than on Earth?

The Chicxulub impact crater in the Yucatan is an easily recognizable crater.

Comets typically orbit the sun at the distance of Neptune.

The Cretaceous-Tertiary mass extinction was apparently caused by a meteorite that struck

A meteoroid that enters the Earth's atmosphere is called a(n) ________.

Why are ancient impact craters difficult to identify on Earth?

The mass extinction at the Permian-Triassic transition definitely resulted from meteorite impact.

Why do some asteroids leave the asteroid belt and cross the orbits of Earth and other solar system bodies?

A meteorite is

The shock wave resulting from meteorite impact causes metamorphism and melting of rocks at and near the Earth's surface.

In 1908, the Tunguska River Valley in Siberia experienced

Blowing a threatening extraterrestrial object into small pieces would likely increase the hazard to Earth.

An asteroid or comet that strikes the Earth's surface is called a meteor.

Asteroids are concentrated in the Oort Cloud, beyond Neptune.

A(n) ________ event is characterized by the sudden loss of large numbers of plants and animals relative to the number of new species being added.

The Tunguska event resulted from impact of a large meteorite.

In 1994, the comet Shoemaker-Levy 9 collided with

Impact of a large extraterrestrial object is probable within the next century.

The elimination of a large proportion of species on Earth is called a(n) ________.

What element was found to be enriched in a thin clay layer marking the Cretaceous-Tertiary boundary at several sites around the world?