Crater depth

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The depth of an impact crater in a solid planet or moon may be measured from the local surface to the bottom of the crater, or from the rim of the crater to the bottom.

Impact crater Circular depression on a solid astronomical body formed by a hypervelocity impact of a smaller object

An impact crater is an approximately circular depression in the surface of a planet, moon, or other solid body in the Solar System or elsewhere, formed by the hypervelocity impact of a smaller body. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters typically have raised rims and floors that are lower in elevation than the surrounding terrain. Impact craters range from small, simple, bowl-shaped depressions to large, complex, multi-ringed impact basins. Meteor Crater is a well-known example of a small impact crater on Earth.

Planet Class of astronomical body directly orbiting a star or stellar remnant

A planet is an astronomical body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.

Natural satellite astronomical body that orbits a planet

A natural satellite, or moon, is, in the most common usage, an astronomical body that orbits a planet or minor planet.

Crater depth diagram Crater-depth-diagram.svg
Crater depth diagram

The diagram above shows the full (side) view of a typical crater. Depth "A" measures from the surface to the bottom of the crater. Depth "B" measures from the mean height of the rim to the bottom of the crater.

Concepts and Measurement

Using the following concepts, a crater is measured:

A method of measuring a crater is to find the length of the shadow cast by the crater's rim and the angle at which the light source enters. In this measurement, use the geometry of triangles to calculate d (shadow depth) using L (shadow length) and Ø (shadow angle). So, tan Ø = d/L and L * tan Ø = d [1]

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References

  1. 1 2 "Crater Depth", National Optical Astronomy Observatory, Retrieved February 29, 2016