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Space Rocks

Impacts of our smallest neighbors

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Asteroid Belt

Asteroid Belt

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The four inner planets formed, but Jupiter’s huge gravity caused

chaos in the region past Mars. No big planet ever formed there

Primitive Solar System

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Craters in the Inner Solar System

Mars’s Southern HighlandsMercury

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Impacts on Moons

Mars’s tiny moon Phobos

Mimas, a moon of Saturn

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Lunar Cratering

Our Moon shows a history of impacts

Most of these occurred long ago…

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The Asteroid Belt is Sparse

On average, there are more than 1 million km between asteroids

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DynamicCollisionsDo Occur

And the effects are seen throughout the Solar System

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Jupiter Shows Recent ImpactsThe world watched as a

comet collided with Jupiter in 1994

Possibly not as rare as we thought. Other collisions have occurred since, like

this one in 2009

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More than 170 Impact Craters on Earth

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Earth Erases History of Impacts

Wolf Creek, Australia

Roter Kamm, Namibia

Barringer Crater, Arizona

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Chicxulub and the Dinosaurs

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Recent Earth Impacts

Tunguska in Russia 1909

2008 TC3- first celestial object

tracked by astronomers before entering Earth’s atmosphere

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MeteoritesChunks of asteroids sometimes make it through

the atmosphere to the ground

These are time capsules telling us about how matter came together in the early Solar System

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Future Impacts• Meteoroids smaller than a house will

explode in our atmosphere5-10 meter objects hit about once a year

• Larger objects are rare but devastating

We don’t know when the next big impact will happen, but it will eventually

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Can we Stop an Impact?Our best chance of avoiding an impact is having advance notice of a threat

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NASA’s WISE Mission

Using Infraredtechnology to see dark asteroids WISE finds asteroids - including

some seen for the first time 100,000s of Main Belt Asteroids 100s of Near-Earth Objects

(NEOs)

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The Challenge Could be OursIf we do find an asteroid headed for Earth…