Macrobius (crater)

Macrobius (crater)
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Title	Macrobius (crater)
Coordinates	21.3, N, 46.0, E...
Diameter	64 km
Depth	1.3 km
Colong	314
Eponym	Macrobius Ambrosius Theodosius

Macrobius (crater). Macrobius is a prominent lunar impact crater located in the northeastern quadrant of the Moon's near side, situated to the east of the Mare Crisium. It is a well-preserved formation with a complex, terraced inner wall and a small central peak, making it a significant feature for telescopic observation. The crater's floor is relatively flat and has a lower albedo than its bright, ray-covered surroundings, which are part of the extensive ejecta system from the younger crater Tycho.

Description

Macrobius is classified as a complex crater, exhibiting a sharp, polygonal rim that rises significantly above the surrounding terra. The inner walls display extensive slumping and terracing, a result of gravitational collapse following the initial impact event. A distinct central peak formation rises from the otherwise flat floor, which is believed to be composed of impact melt and breccia. The crater's exterior is overlain by bright rays and secondary crater chains, most notably from the distant Tycho, though it also possesses its own system of ejecta. To its northwest, the rim is overlapped by the smaller, bowl-shaped crater Tisserand, while the lava-flooded remains of Macrobius A are attached to its southern rim. The region around Macrobius is geologically diverse, featuring both the rugged highlands of the Lacus Bonitatis area and the smoother plains bordering Mare Crisium.

Satellite craters

By convention, these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Macrobius. The most notable satellite craters include Macrobius A, a flooded formation intruding on the southern rim, and Macrobius B and Macrobius C, which are smaller, more eroded impacts to the east. Macrobius D is located to the northwest, and Macrobius F lies to the southwest, both being relatively fresh craters. Macrobius E is a deep, bowl-shaped crater situated further to the southeast. These satellite formations, along with many other smaller impacts, provide context for understanding the stratigraphy and relative ages of surfaces in this region of the Moon.

Etymology

The crater is named for the late Roman grammarian, philosopher, and Neoplatonist Macrobius Ambrosius Theodosius, who lived in the early 5th century AD. His most famous work, the Saturnalia, is a compendium of Roman antiquarian and philosophical lore presented as a series of dialogues. The name was officially adopted by the International Astronomical Union (IAU) following its standardization of lunar nomenclature, in keeping with the tradition of naming craters in this region after classical scholars and philosophers. This naming convention places Macrobius among other craters honoring ancient figures, such as nearby Cleomedes and Proclus.

Related features

Macrobius is a key landmark in the highlands between Mare Crisium and Mare Serenitatis. To its west lies the distinctive, elongated crater Cleomedes, and to the southwest is the bright-rayed crater Proclus. The region is also home to the sinuous rille system Rima Cleomedes and the larger, flooded plain of Lacus Bonitatis. The crater's rays and ejecta interact with those from the much larger and younger Tycho, which is located over 2,000 kilometers to the southwest. This interaction provides valuable information for studies of impact stratigraphy conducted by missions like NASA's Lunar Reconnaissance Orbiter.

Category:Impact craters on the Moon