Saturday, October 9, 2010

Interior of complex crater Eratosthenes

Simulated view over the interior of Eratosthenes, LROC WAC local late afternoon observation draped over the low-resolution digital elevation model available at this location on the Moon in Google Earth. The central peak and slumped interior walls of the crater, detail below, are seen in this view, seen from 27.5 km overhead. The crater is buttressed against the southwestern terminus of the 978 km-long Montes Apenninus, which seem concentric to the Mare Imbrium impact but may, instead, be the outer rim of a more ancient impact. Kaguya ground-penetrating radar in parts of Imbrium may confirm the existence of basalt flows buried by the primary Imbrium event, 3.9 billion years ago. At upper right, 3500 meter high Mons Wolff is the first of Apenninus' high peaks, as the chain curves further north by northeast over the horizon [NASA/GSFC/ASU/Google].

Drew Enns
LROC News System

Like many complex craters on the Moon, Eratosthenes (14.5°N, 348.7°E) exhibits terraces within its rim. Terraces form as interior walls of the crater slump over time, creating a landslide while leaving the upper portion of the wall intact. LROC Narrow Angle Camera (NAC) image M119924207R; LRO orbit 2807, February 4, 2010; alt. 38.5 km, resolution 0.61 cm, phase angle 53.15° field of view = 600 meters [NASA/GSFC/Arizona State University].

Eratosthenes crater (LROC WAC mosaic). Featured NAC image location denoted by the white box. (Context Image field of view is 100 km. Brighter, younger more reflective ejecta from Copernicus radiating from the southwest is easily seen [NASA/GFSC/Arizona State University].

Explore the rest of the terraces in the full NAC image.

Related Posts: Necho's Terraces

Sunrise over Eratosthenes central peak summit. From LROC NAC image M131725388L; LRO orbit 4546, June 21, 2010; Res. 59 cm per pixel. Image field of view = 600 m [NASA/GFSC/Arizona State University].

Central peaks occur in complex craters as a result of the ground rebounding against the initial impact. They can even help cause the formation of terraces. The boulders in the image are either being weathered out of the central peak, or are ejecta from nearby craters such as Copernicus crater.

LROC NAC View of another portion of Eratosthenes' central peak, complete with boulder tracks (Downslope is to the right.) from the same LROC NAC observation M131725388L, image field of view is also is 600 meters [NASA/GSFC/Arizona State University].

Discover the transition from the central peak to the crater rim of Eratosthenes in the full NAC image!

Related Posts: Up from the depths

Eratosthenes Crater and the Lunar Timescale

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