| 11. | Impact craters larger than about 250 km are referred to as basins.
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| 12. | Many planets and moons have impact craters dating back large spans of time.
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| 13. | The density of impact craters varies across the surface of Tethys.
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| 14. | The floor is free of significant impact craters and lacks a central peak.
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| 15. | They are sometimes confused with meteors because they can leave small impact craters.
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| 16. | Several prominent impact craters and catenae are located within Valhalla structure.
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| 17. | There is an impact crater on Mars named in his honor.
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| 18. | The former is a remarkably flat area with a lot of impact craters.
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| 19. | Other features of Meridiani Planum include volcanic basalt and impact craters.
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| 20. | Almost a thousand impact craters on Venus are evenly distributed across its surface.
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