Impact CratersLeave an Impression…

Andy Saulietis

Craters are everywhere!

The Moon

LPL / UA

NASA Apollo 17

Mercury

NASA/GSFC

Asteroids

NASA

NASA

Mars

NASA

Even Earth…

Meteor Crater, AZ

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So what causes craters?

Asteroids and Comets!

NASA

•Left over building blocks of the solar system (~5 billion years old)

•Vary in size, from a few feet to a few miles

•Millions of potential meteors in our solar system alone

•Travel in excess of 20,000 mph

When these objects collide with another body, like the Earth, the result is a crater.

Meteor Crater, AZ

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•Size: 150 Feet Across1

•Composition: Nickel-Iron1

•Speed: 28,600 MPH1

•Age: 50,000 years old1

•Energy: 2.5 Megatons1

1Barringer Meteor Crater Site

http://www.barringercrater.com/

NASA/GSFC

Shoemaker-Levy 9

Why do some planets have more craters than others?

NASA/GSFC

•Atmosphere

•Oceans

•Plate Tectonics

•Location

So why do we care?

NASA/GSFC

Extinction

Extinction

•Estimated that there have been at least 5 mass-extinctions in Earth’s history1

•Up to 90% of all species killed off2

•At least one is believed to have been caused by a meteorite1

•65 Million Years ago, Yucatan Penninsula2

•>100 Miles across2

•Force Greater than 1,000,000 megatons3 1 Lee Siegel, space.com

2 NASA/GSFC

3 Arnett, Bill, UA