Planetary Impacts

  • Exhibition Text

    • Impacts have played an important role throughout the history of the solar system. During the formation epoch, impacts built up the planets. A period of intense bombardment continued for hundreds of millions of years, with life on Earth developing only afterward. Impact craters are the dominant surface feature on the Moon, Mercury, and many moons of the gas giant planets. On Earth, a comet or asteroid impact contributed to the extinction of the dinosaurs. Impacts can affect the long-term evolution of life, and the question of future catastrophic impacts is not if, but when.

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  • For Educators

    • Topic: Astronomy

      Subtopic: Planets

      Keywords: Life (Biology), Solar system, Planets--Surfaces, Impact craters, Extinction (Biology)

      Audience: General

In This Section

The Willamette Meteorite

The Willamette Meteorite

Billions of years ago, an early planet orbiting the Sun was shattered, perhaps in a collision with another protoplanet.

Meteors and Meteorites

Meteors and Meteorites

Meteors, also known as shooting stars, are pebble-size fragments of comets and asteroids streaking through Earth’s upper atmosphere.

Asteroids

Asteroids

Asteroids are small, rocky worlds with generally irregular shapes.

Comets

Comets

Comets are kilometer-size snowballs made of ice and dust. 

Impact Excavation

Impact Excavation

The hypervelocity impact of a 1-centimeter meteorite on an airless, rocky world would excavate a crater as large as the circular area of this exhibit.