Two different NAC images of the pit with different incidence angles. Red arrows point to the same features in both images. The blue arrows point to the pit itself [NASA/GSFC/Arizona State University].
Impact melt pits are a type of lunar feature now seen in many LROC NAC images. This LROC image shows a newly discovered pit within the impact melt of a relatively small, unnamed crater. The pit is roughly circular with a diameter of ~16 meters. This diameter is smaller than the large pits found in mare basalt: the Mare Ingenii pit is ~130 m in diameter, the Marius Hills pit is ~65 m in diameter, and the Mare Tranquillitatis pit is ~100 m in diameter.
Pits like this may have formed when a portion of a lava tube collapsed. The subsequent pit is a skylight that leads into the intact lava tube.
Higher sun angle images allow scientists to calculate the depth of this impact melt pit. In the image above, two observations give a slightly different view of the main pit (blue arrow) and the irregular fracture (which could be a second pit) to the west (red arrow on the left), but the floor of the pit is not visible at either incidence angle.
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Posted by:Soderman/NLSI Staff