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Copernican Period
The Copernican Period in the lunar geologic timescale runs from approximately 1.1 billion years ago to the present day. The base of the Copernican period is defined by impact craters that possess bright optically immature ray systems. The crater Copernicus is a prominent example of rayed crater, but it does not mark the base of the Copernican period. Copernican age deposits are mostly represented by crater ejecta, but a small area of mare basalt has covered part of (and is thus younger than) some of the rays of the Copernican crater Lichtenberg, and therefore the basalt is mapped as Copernican age. Definition The base of the Copernican period is defined based on the recognition that freshly excavated materials on the lunar surface are generally "bright" and that they become darker over time as a result of space weathering processes. Operationally, this period was originally defined as the time at which impact craters "lost" their bright ray systems. This definition, howeve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Geologic Timescale
The lunar geological timescale (or selenological timescale) divides the history of Earth's Moon into five generally recognized periods: the Copernican, Eratosthenian, Imbrian ( Late and Early epochs), Nectarian, and Pre-Nectarian. The boundaries of this time scale are related to large impact events that have modified the lunar surface, changes in crater formation through time, and the size-frequency distribution of craters superposed on geological units. The absolute ages for these periods have been constrained by radiometric dating of samples obtained from the lunar surface. However, there is still much debate concerning the ages of certain key events, because correlating lunar regolith samples with geological units on the Moon is difficult, and most lunar radiometric ages have been highly affected by an intense history of bombardment. Lunar stratigraphy The primary geological processes that have modified the lunar surface are impact cratering and volcanism, and by using ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eudoxus (lunar Crater)
Eudoxus is a prominent lunar impact crater that lies to the east of the northern tip of the Montes Caucasus range. It is named after the Greek astronomer Eudoxus of Cnidus. It is located to the south of the prominent crater Aristoteles in the northern regions of the visible Moon. To the south is the ruined formation of Alexander, and the small crater Lamèch lies to the southwest. The rim of Eudoxus has a series of terraces on the interior wall, and slightly worn ramparts about the exterior. It lacks a single central peak, but has a cluster of low hills about the midpoint of the floor. The remainder of the interior floor is relatively level. Eudoxus has a ray system, and is consequently mapped as part of the Copernican System.The geologic history of the Moon, 1987, Wilhelms, Don E.; with sections by McCauley, John F.; Trask, Newell J. USGS Professional Paper: 1348. Plate 11: Copernican Systemonline File:Aldo Ferruggia - Lacus Mortis.jpg, Eudoxus and closer structures with mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
King (crater)
King is a prominent lunar impact crater that is located on the far side of the Moon, and can not be viewed directly from Earth. The crater was named after Arthur Scott King and Edward Skinner King in 1970. Prior to that, this crater was known as ''Crater 211''. It forms a pair with Ibn Firnas, which is only slightly larger and is attached to the northeast rim of King. To the northwest is the crater Lobachevskiy, and Guyot is located an equal distance to the north-northwest. Description The outer rim of King is roughly circular but with a slightly irregular appearance, particularly at the northern end. The crater displays little appearance of wear. The inner walls are terraced, particularly along the eastern side. Within the walls is a somewhat uneven interior floor. The interior is irregular and ridged, particularly in the eastern half. The elongated, Y-shaped central rise is part of a ridge that runs to the southern rim. Due to its prominent rays, King is mapped as part of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jackson (crater)
Jackson is a prominent lunar impact crater that is located in the northern hemisphere on the far side of the Moon. Less than one crater to the northeast is the crater Mineur, and to the south-southwest lies McMath. This crater created a large ray system. A skirt of higher-albedo material covers the surface within one crater diameter, with a slightly darker band along the outer ramparts. Beyond that radius, the rays form wide sections that grow increasingly diffuse and wispy with distance. The largest sections lie in roughly 90° arcs to the northeast and southwest, while a narrower arc projects to the south-southeast. The rays continue for hundreds of kilometers across the surface. The rim of the crater is well-defined and not significantly worn. The edge is somewhat polygonal in shape, with the southeastern rim being more rounded. The inner walls display some terracing. The interior floor is generally level with some irregularities in the northeastern part. Parts of the floor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ohm (crater)
Ohm is a lunar impact crater that is located on the far side of the Moon. It lies to the south of the crater Comrie, and the satellite crater Comrie K is attached to Ohm's northeastern rim. To the northwest is the larger Shternberg, and to the southwest is Kamerlingh Onnes. This crater is located at the origin of an extensive ray system that extends for several hundred kilometers across the surrounding lunar terrain. The exterior surface for about 20–30 km is relatively free of the ray material, but beyond that perimeter is a skirt of higher albedo Albedo (; ) is the measure of the diffuse reflection of solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that refl ..., with streaks extending to the northwest, east-northeast, and southwards. The crater is part of the Copernican System. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rutherfurd (crater)
Rutherfurd is a lunar impact crater located entirely within the southern rim of the much larger crater Clavius. The crater Porter is located to the north-northeast of Rutherfurd, on the northeastern rim of Clavius. Rutherfurd forms the larger member in an arcing chain of craters of decreasing size that curves across the floor of Clavius. The craters in this chain do not appear to be the same age, so this formation is most likely random in nature. Rutherfurd is somewhat oval in shape, with the long axis oriented approximately in a north–south direction. The northern outer ramparts have a series of radiating ridges on the floor of Clavius. The rim overlies the inner wall of Clavius, and thus the rim of Rutherfurd is higher above the surface along the north and west sides. The floor is irregular in shape, and there is a central peak somewhat offset to the northeast. The ejecta pattern, oblong shape, and location of the central peak indicate the original impact may have been at a low ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zucchius (crater)
Zucchius is a prominent lunar impact crater located near the southwestern limb. Because of its location the crater appears oblong-shaped due to foreshortening. It lies just to the south-southwest of the crater Segner, and northeast of the much larger walled plain Bailly. To the southeast is Bettinus, a formation only slightly larger than Zucchius. The crater rim is symmetrical and shows little significant wear from impacts. The inner wall is terraced, and there is a group of small central peaks that forms a curving arc around the middle of the floor, making it a complex crater. Due to its ray system, Zucchius is mapped as part of the Copernican System. To the northeast of Zucchius is the Schiller-Zucchius Basin, a Pre-Nectarian The pre-Nectarian period of the lunar geologic timescale runs from 4.533 billion years ago (the time of the initial formation of the Moon) to 3.920 billion years ago, when the Nectaris Basin was formed by a large impact. It is followed by the Necta . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hayn (crater)
Hayn is a lunar impact crater that lies next to the northeast limb of the Moon. This location restricts the amount of detail that can be viewed from the Earth, as the western inner side is permanently hidden from sight. Observation of this crater can also be affected by libration, which can completely hide this crater from sight. This crater lies across the northwestern rim of the walled plain Bel'kovich, to the north of the Mare Humboldtianum. It is otherwise relatively isolated from other named craters, with the nearest being Cusanus to the northwest. This is a young crater with a rim and interior that have not yet been significantly eroded. It has a circular but somewhat uneven rim and an inner wall containing a number of terraces. The southern rim is slightly more pronounced in height where it joins the heavily worn rim of Bel'kovich. There is also an outer rampart beyond the rim that is more extensive to the southwest. Of the rim of Bel'kovich to the east of Hayn there is lit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glushko (crater)
Glushko is a young impact crater on the Moon attached to the western rim of the crater Olbers. Glushko possesses a relatively high albedo and is the focus of a prominent ray system that extends in all directions across the nearby surface. It has sharp, well-defined features that, combined with its higher albedo, are indicative of a relatively young impact crater. There is a small outer rampart, and material along the inner walls has slumped to form shelves and ramparts. There are three outward bulges in the rim to the north and northwest. Due to its prominent rays, Glushko is mapped as part of the Copernican System.The geologic history of the Moon, 1987, Wilhelms, Don E.; with sections by McCauley, John F.; Trask, Newell J. USGS Professional Paper: 1348. Plate 11: Copernican Systemonline This crater was previously designated Olbers A before being renamed by the IAU The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anaxagoras (crater)
Anaxagoras is a young lunar impact crater that is located near the north pole of the Moon. It lies across the larger and more heavily worn crater Goldschmidt. To the south-southeast is Epigenes, and due south is the worn remains of Birmingham. Anaxagoras is a relatively recent impact crater that is young enough to still possess a ray system that has not been eroded by space weathering. The rays from the site reach a distance of over 900 kilometers from the rim, reaching Plato to the south. It is consequently mapped as part of the Copernican System.The geologic history of the Moon, 1987, Wilhelms, Don E.; with sections by McCauley, John F.; Trask, Newell J. USGS Professional Paper: 1348. Plate 11: Copernican Systemonline The crater interior has a relatively high albedo, making it a prominent feature when the Moon is nearly full. (The high latitude of the crater means that the Sun always remains close to the horizon even at maximum elevation less than a day after Full Moon.) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philolaus (crater)
Philolaus is a lunar impact crater that is located in the northern part of the Moon's near side. It lies within one crater diameter to the east-southeast of the flooded crater Anaximenes, and to the west of the smaller Anaxagoras. It overlies the older and heavily worn Philolaus C to the south. This crater retains a well-defined form that has not changed significantly since it was originally created. The outer rim edge is roughly circular, but with a somewhat irregular edge that displays signs of slumping. The most notable slump is a triangular area along the eastern rim. The inner wall of the crater has a complex system of terraces with a sharp-edged rim in locations where slumping has occurred. On the exterior of the rim is an outer rampart that extends outwards for nearly half a crater diameter in all directions. The crater has a ray system, and is consequently mapped as part of the Copernican System.The geologic history of the Moon, 1987, Wilhelms, Don E.; with sections by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
