An intersection of two fractures in the crater Gassendi forms a rough "Y," with boulders concentrated on the northern wall. LROC Narrow Angle Camera observation M104770486L, LRO orbit 597, August 13, 2009. Image field of view is 946 meters, and the solar illumination incidence angle is 51 degrees [NASA/GSFC/Arizona State University].
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The crater Gassendi is 110 kilometers in diameter and located on the northern edge of Mare Humorum at 17.5°S, 320.1°E. Gassendi features an array of intersecting fractures on its floor, collectively known as the Rimae Gassendi.
The LROC featured image nested within the boundaries of the full Narrow Angle Camera observation and the LROC Wide Angle Camera mosaic below. What seems relatively close by is Gassendi's northern rim, more than 40 kilometers away.
Some of the largest fractures are thousands of meters wide. The origin of these fractures in the floor of Gassendi is not known for certain. After the impact the floor of Gassendi was molten and as it cooled, a crust of solid material formed at the surface. As the entire crater floor continued to cool and settle into its final shape, fractures could have formed due to the forces caused by these changes. Other craters besides Gassendi also have fractured floors, like the craters Alphonsus or Goclenius. How do you think fractures form inside craters? What are the differences between each of these craters?
Meets and Bounds of the LROC NAC observation and location of the "Y" intersection in the featured image. The full WAC mosaic can be seen here [NASA/GSFC/Arizona State University].
Examine the fractures by viewing the full NAC frame!
Gassendi's Central Peak
Alphonsus crater mantled floor fracture