Thursday, September 23, 2010

Optically immature ("low OMAT") lunar surfaces

This crater in the floor of Van de Graaff has a high reflectance ejecta blanket compared to the surrounding low reflectance material. The contrast in albedo is due to the crater excavating "fresh" or "immature" material from underneath the surface. Next image field of view is 650 meters. LROC Narrow Angle Camera image M110472904R; 30° incidence angle [NASA/GSFC/Arizona State University].

- Sarah Braden
LROC News System

Ed. Note: Zooming in upon the LROC Narrow Angle Camera observation (M110472904R) affords up an opportunity to see what some have theorize to be two very different kinds of "optically immature" lunar surfaces, areas with "low OMAT." The higher albedo of rough material excavated by the subject crater is particularly highlighted in having apparently occurred directly in a dark lane, bifurcating brighter "swirl" patterns often coincident with local crustal magnetic anomalies on the Moon. In 900 million years the crater's fresh ejecta will have become reddened, darkened into the darker background. Meanwhile the surfaces inside the influence of the local magnetic field lines might well be little changed. Though such fields give no protection against micrometeorites or galactic cosmic rays, they have been shown elsewhere on the Moon to be intense enough to form mini-magnetospheres, deflecting the ever-present solar wind. LROC NAC observation swept up in LRO orbit 1414, October 18, 2009 [NASA/GSFC/Arizona State University].

Browse the full-resolution NAC image in our LROC Image Gallery!

Related posts:

Crater wall in Van de Graaff Constellation ROI
Ejecta from Van de Graaff Crater

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