Curved boulder tracks outside the rim of a fresh crater. LROC NAC M143594908L, image width is 440 meters [NASA/GSFC/Arizona State University].

The boulders in the Featured Image all curve to the northeast, carving dark paths across the fresh rays from a small 525-m diameter crater (located on the lunar farside, northeast of Van Gent U, 17.233°N, 157.367°E). The boulders originated from the impact crater itself, being ejected during the impact event with a velocity radial to the crater rim. As the boulders bounced and rolled along the surface they lost speed (kinetic energy) and slowed, creating gently curving paths until they came to a stop. The curved paths are likely caused by the preexisting slope of the topography, which is slightly downward sloping to the northeast (~10°). The linear striations of the fresh ejecta define the radial direction away from the crater and provide a beautiful contrast for the curved boulder paths. Overall, the fresh material was ejected at higher velocities than the boulders so it is not influenced by the topography and remains on a trajectory radial to the crater.

NAC context image showing the location of the boulders with respect to the source crater. Image width is 1.9 km [NASA/GSFC/Arizona State University].

Explore the entire fresh crater with the LROC NAC!

Related Images:

Hole in One!

Bounce, Roll, and Stop

Weaving Boulder Trails on the Moon

Rolling Rolling Rolling

Sampling Schroedinger

Central Peak/Mare Boundary

Published by Sarah Braden on 25 June 2013