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The Winter 2010 issue of The Earth Scientist includes a variety of educational resources, ranging from astronomy to glaciers. Check out the other publications and classroom materials in our online store.
This is an image of the surface of Mercury.
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NASA

Early Cratering of the Planets

When we look at images of many of the planets, we see all sorts of circular craters on the planet surfaces. Most of these craters were probably formed when the solar system was still very young.

Once the early solar system had planets about the size of the planets today, there were still probably a lot of smaller bodies around, too. The gravity of the large planets would pull in nearby smaller bodies, which would hit the planets and leave a crater on the planet's surface.

Craters on the surfaces of the inner planets are up to 4,000 million years old, and some craters seem to have been made by objects up to 200 km across!


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The Summer 2010 issue of The Earth Scientist, available in our online store, includes articles on rivers and snow, classroom planetariums, satellites and oceanography, hands-on astronomy, and global warming.

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