This spiral-shaped feature may have formed due to shear stress created when molten impact melt flowed at different speeds (probably caused by drag from the pool floor or an obstacle within the pool). The whorl formed in a clockwise direction and is ~1 km in diameter. The crater Giordano Bruno is a favorite of lunar scientists due to its relatively young age and the amazing impact melt features found within and without the crater walls.This image uses a 57 cm per pixel Narrow Angle Camera frame to highlight the details of a giant swirl (or whorl) of impact melt within one of the larger impact melt pools inside Giordano Bruno. So this flow is probably granular, not molten. The crater is not large enough to develop terraces where impact melt can pool and then flow out. Second, in this particular NAC frame there is no evidence for impact melt deposits around the rim of the crater, although you can find evidence of impact melt in the crater floor. This location most likely means that we are not observing a compositional difference, as there are no nearby sources of mare basalt that could account for the low-reflectance material. First, the crater is located on the far side of the Moon, in an area of highlands. Some quick observations can point us in the right direction. What is the cause of the low reflectance of this material? How is it different from the high reflectance crater wall? Are the differences caused by composition, grain size, or both? Also, is this flow a granular flow, or an impact melt flow? Sometimes these two types of flow can behave similarly. When geologists describe different surfaces on the Moon or other planetary objects, we use the terms "high reflectance" and "low reflectance." In this case, the wall of the crater is high reflectance, but some of the material that has flowed down the wall is low reflectance. The wall of this 8.5 km diameter, Copernican-aged crater (located at 3.29°N, 100.25°W) is streaked with dark material. High resolution images of these very fresh craters supply key information about impact cratering, which improves our knowledge of the craters and helps to reveal the history of any airless planetary bodies in our solar system.
Apparently, ejecta that landed far away from the impact center settled on the ground earlier than the portion that traveled a shorter distance. This beautiful ejecta field consists of numerous lobes systematically piled on the top of adjacent outer lobes, resulting in a view like a stop motion picture of the impact event. The numerous dark dots intermixed with the high reflectance ejecta might be same dark materials as the one on the crater floor, or more likely secondary craters excavating the background mature material. The low reflectance materials in the center of this crater are probably impact melts or a different rock type in the subsurface that was excavated by the impact. The strong reflectance contrast between the ejecta deposit and the surrounding background in the opening image suggests that this crater is still very flesh and young. This image highlights an unnamed small crater (roughly 180 m in diameter) located at the northern edge of Mare Fecunditatis, near the crater chain known as Catena Taruntis.
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