Tuesday, January 25, 2011

Terraced Craters in Aitken Crater

Small crater within Aitken has a terraced and hummocky floor with boulders strewn about and no bright rays (though when seen in context, below, is situated within a larger debris ray or area of anomalously optically immature regolith. LROC Narrow Angle Camera observation M145855135, LRO orbit 6628, December 1, 2010. Crater is roughly two kilometers wide [NASA/GSFC/Arizona State University].

Drew Enns
LROC News System

This crater has an unusual floor for its size. An impact crater of this size typically has a simple bowl shape, yet this example displays terraces and hummocks. The terraces give us insight into the impact material. A bolide that impacts a solid surface covered by loose material, for example mare covered by regolith, will use less of its energy to break up the loose material than solid material. The "excess" energy goes into excavating more material thus making for a larger diameter. Thus we see terrace at the boundary between the regolith and underlying more coherent material. The fact that the crater has no bright rays indicates that it is old - its rays have weathered into the background.

Location of the terraced crater (LROC Featured Image. January 25, 2011) within the landmark farside crater Aitken (16.8° S 173.4° E) [NASA/GSFC/Arizona State University].

Find more craters in the full NAC frame!

Related Posts:
Wrinkle Ridges in Aitken Crater
Aitken Central Peak, Seen Obliquely
Approaching Aitken Crater - Vertregt J

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