Ejecta Interference Patterns

A 960 meter-wide portion of an unnamed young crater's distinctive ejecta deposit pattern, 330 km west-southwest of Kepler in Oceanus Procellarum. LROC Narrow Angle Camera (NAC) observation M188557336R, LRO orbit 12847, April 8, 2012; field of view centered on 3.972°N, 311.942°E, resolution 95 cm per pixel, angle of incidence 21.1° from 114.25 km [NASA/GSFC/Arizona State University].

Hiroyuki Sato
LROC News System

Today's Featured Image highlights a portion of a very fresh ejecta deposit. The source crater is an unnamed crater about 1.2 km in diameter, located within Oceanus Procellarum.

As seen in the NAC context view below, the higher reflectance ejecta spreads radially from the crater, and in some regions may have formed interference patterns that look a bit like fish scales.

The opening image focuses on a typical portion showing this geometric pattern.

Near the full 5.4 km width of the field of view within the footprint of LROC NAC M188557336R, a context view for the scope of the LROC Featured Image (yellow box) at reduced resolution. [NASA/GSFC/Arizona State University].

In the vacuum of space, the ejected materials experience no atmospheric drag, and thus no fluid dynamic instabilities driven by such an interaction occur. How then was this sparse/dense ejecta pattern formed? The advancing ejecta curtain probably already had internal density contrasts that produced greater or lesser collision frequencies among the admixed rock fragments. Portions having regular density at intervals with portions have irregular density might have formed this odd, scaly pattern.

Context view of the unnamed young crater and vicinity, a LROC WAC monochrome mosaic (100 meters resolution) centered near 3.96°N, 311.94°E. LROC NAC M188557336R footprint represented by a blue rectangle with the location of LROC Featured Image field of view designated with an arrow [NASA/GSFC/Arizona State University].

At full resolution, the area of interest (arrow) is visible in a mosaic of 21 telescopic images stacked on Earth, January 13, 2009. (Note the bright ray from Kepler crossing hundreds of kilometers over and past the vicinity of the unnamed crater, visible from Earth in the midst of the wide middle expanse of Oceanus Procellarum. Field of view is shown context with a reduced view of the complete mosaic below [ASTRONOMINSK].

Explore the exotic patterns of this young crater ejecta in full NAC frame yourself, HERE.

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