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Rhaeticus (crater)
Rhaeticus is a lunar impact crater that lies astride the equator of the Moon, on the southeast edge of the Sinus Medii. To the north-northwest is the crater Triesnecker, and due south can be found the worn remnant of the walled plain Hipparchus. The crater was named after Austrian astronomer Georg Joachim Rheticus.''Autostar Suite Astronomer Edition''. CD-ROM. Meade, April 2006. Description The outer wall of Rhaeticus is heavily disintegrated, with rifts and notches in the northeast. The wall is most intact along the eastern face, while in the northwest it is little more than a low rise in the surface. There is also a low cut in the south-southeast wall. The overall shape of the rim is that of a rough hexagon that is slightly elongated in the north–south direction. The interior has been resurfaced by lava, and only a few low rises remain in the surface. Beginning at the crest of the eastern wall is a chain of craterlets that continue to the east-northeast for about a crater dia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Orbiter 4
Lunar Orbiter 4 was a robotic U.S. spacecraft, part of the Lunar Orbiter program, Lunar Orbiter Program, designed to orbit the Moon, after the three previous orbiters had completed the required needs for Project Apollo, Apollo mapping and site selection. It was given a more general objective, to "perform a broad systematic photographic survey of lunar surface features in order to increase the scientific knowledge of their nature, origin, and processes, and to serve as a basis for selecting sites for more detailed scientific study by subsequent orbital and landing missions". It was also equipped to collect selenodetic, radiation intensity, and micrometeoroid impact data. Mission Summary The spacecraft was placed in a Free-return trajectory, cislunar trajectory and injected into an elliptical near polar high lunar orbit for data acquisition. The orbit was with an inclination of 85.5 degrees and a period of 12 hours. After initial photography on May 11, 1967 problems started occu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hipparchus (lunar Crater)
Hipparchus is the degraded remnant of a lunar impact crater. It was named after the Greek astronomer, geographer and mathematician Hipparchus. It is located to the southeast of Sinus Medii, near the center of the visible Moon. To the south is the prominent crater Albategnius, and to the southwest lies Ptolemaeus, a feature of comparable dimensions to Hipparchus. Horrocks lies entirely within the northeast rim of the crater. Halley is attached to the south rim, and Hind lies to the southeast. To the north-northeast is the bowl-shaped Pickering, and the flooded Saunder is located off the northeast rim. High-resolution images of Hipparchus were obtained by Lunar Orbiter 5 in 1967. Description This feature is an ancient crater that has been subject to considerable modification due to subsequent impacts. The western rim of Hipparchus has been all but worn away from impact erosion, and only low hills and rises in the surface remain to outline the feature. The wall to the east is s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambridge University Press
Cambridge University Press is the university press of the University of Cambridge. Granted letters patent by Henry VIII of England, King Henry VIII in 1534, it is the oldest university press A university press is an academic publishing house specializing in monographs and scholarly journals. Most are nonprofit organizations and an integral component of a large research university. They publish work that has been reviewed by schola ... in the world. It is also the King's Printer. Cambridge University Press is a department of the University of Cambridge and is both an academic and educational publisher. It became part of Cambridge University Press & Assessment, following a merger with Cambridge Assessment in 2021. With a global sales presence, publishing hubs, and offices in more than 40 Country, countries, it publishes over 50,000 titles by authors from over 100 countries. Its publishing includes more than 380 academic journals, monographs, reference works, school and uni ... [...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 period, Copernican, Eratosthenian, Imbrian (Late Imbrian, Late and Early Imbrian, 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 impact crater, 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 sur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rille
Rille (German for 'groove') is typically used to describe any of the long, narrow depressions in the surface of the Moon that resemble channels. The Latin term is ''rima'', plural ''rimae''. Typically, a rille can be several kilometers wide and hundreds of kilometers in length. However, the term has also been used loosely to describe similar structures on a number of planets in the Solar System, including Mars, Venus, and on a number of moons. All bear a structural resemblance to each other. Structures Three types of rille are found on the lunar surface: * Sinuous rilles meander in a curved path like a mature river, and are commonly thought to be the remains of collapsed lava tubes or extinct lava flows. They usually begin at an extinct volcano, then meander and sometimes split as they are followed across the surface. , 195 sinuous rilles have been identified on the Moon. Vallis Schröteri in Oceanus Procellarum is the largest sinuous rille, and Rima Hadley is the only one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Réaumur (crater)
Réaumur is the remains of a lunar impact crater located on the southern edge of Sinus Medii. Its diameter is 51 km. It was named after the 18th century French scientist René de Réaumur. It shares an eroded rim with the similar crater Oppolzer to the northwest. It lies to the northwest of the large walled plain Hipparchus, and east of Flammarion. To the south is Gyldén, and farther to the south-southwest is Ptolemaeus. The rim of Réaumur is heavily eroded, and the northern half consists of little more than a series of low ridges in the mare. The southern rim is notched and indented by small crater impacts. The interior floor is relatively smooth and flat with no significant features. The broken northern rim intersects a rille Rille (German for 'groove') is typically used to describe any of the long, narrow depressions in the surface of the Moon that resemble channels. The Latin term is ''rima'', plural ''rimae''. Typically, a rille can be several kilometers w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava
Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or underwater, usually at temperatures from . The volcanic rock resulting from subsequent cooling is also often called ''lava''. A lava flow is an outpouring of lava during an effusive eruption. (An explosive eruption, by contrast, produces a mixture of volcanic ash and other fragments called tephra, not lava flows.) The viscosity of most lava is about that of ketchup, roughly 10,000 to 100,000 times that of water. Even so, lava can flow great distances before cooling causes it to solidify, because lava exposed to air quickly develops a solid crust that insulates the remaining liquid lava, helping to keep it hot and inviscid enough to continue flowing. The word ''lava'' comes from Italian and is probably derived from the Latin word ''labes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexagon
In geometry, a hexagon (from Ancient Greek, Greek , , meaning "six", and , , meaning "corner, angle") is a six-sided polygon. The total of the internal angles of any simple polygon, simple (non-self-intersecting) hexagon is 720°. Regular hexagon A ''regular polygon, regular hexagon'' has Schläfli symbol and can also be constructed as a Truncation (geometry), truncated equilateral triangle, t, which alternates two types of edges. A regular hexagon is defined as a hexagon that is both equilateral polygon, equilateral and equiangular polygon, equiangular. It is bicentric polygon, bicentric, meaning that it is both cyclic polygon, cyclic (has a circumscribed circle) and tangential polygon, tangential (has an inscribed circle). The common length of the sides equals the radius of the circumscribed circle or circumcircle, which equals \tfrac times the apothem (radius of the inscribed figure, inscribed circle). All internal angles are 120 degree (angle), degrees. A regular hexago ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triesnecker (crater)
Triesnecker is a prominent Lunar craters, lunar impact crater that is located in the Sinus Medii, near the central part of the Moon's near side. Its diameter is 25 km. It was named after Austrian astronomer Franz de Paula Triesnecker. It is located to the north-northwest of the crater Rhaeticus (crater), Rhaeticus, and to the east-southeast of the flooded Murchison (crater), Murchison. The crater rim of Triesnecker is somewhat distorted from a circular shape, having a notable bulge in the western wall, and lesser rises in the southeastern and northeastern rims. The inner walls are terraced and the interior is somewhat rough, with a central peak at the midpoint. Triesnecker has a ray system that is most prominent when the sun is at a high angle. The rays extend over 300 kilometers. To the east of this crater is an extensive system of rilles extending over an area 200 kilometers across, running generally north–south. These were likely created by tectonic forces beneath the surfa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Georg Joachim Rheticus
Georg Joachim de Porris, also known as Rheticus ( /ˈrɛtɪkəs/; 16 February 1514 – 5 December 1576), was a mathematician, astronomer, cartographer, navigational-instrument maker, medical practitioner, and teacher. He is perhaps best known for his trigonometric tables and as Nicolaus Copernicus's sole pupil.Danielson, p. 3. He facilitated the publication of his master's ''De revolutionibus orbium coelestium'' (''On the Revolutions of the Heavenly Spheres''). Surname Rheticus was born at Feldkirch in the Archduchy of Austria. Both his parents, Georg Iserin and Thomasina de Porris, were of Italian heritage and possessed considerable wealth, his father being the town physician as well as a government official. He was educated by his father until the age of 14 when Georg (Iserin) abused the trust of many of his patients, stealing belongings and money from their homes. In 1528 he was convicted and executed for his crimes, and as a result his family was stripped of their surname. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinus Medii
Sinus Medii (Latin ''sinus mediī'' "Middle Bay") is a small lunar mare. It takes its name from its location at the intersection of the Moon's equator and prime meridian; as seen from the Earth, this feature is located in the central part of the Moon's near side, and it is the point closest to the Earth. From this spot the Earth would always appear directly overhead, although the planet's position would vary slightly due to libration. During the Apollo program, Sinus Medii was designated ALS3. Flight operations planners were concerned about having the optimum lighting conditions at the landing site, hence alternative landing sites moved progressively westward, following the terminator. A delay of two days for weather or equipment reasons would have sent Apollo 11 to Sinus Medii instead of ALS2, Mare Tranquillitatis; another two-day delay would have resulted in ALS5, a site in Oceanus Procellarum, being targeted. Geology The selenographic coordinates of Sinus Medii are , and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moon
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of Australia). The Moon is a planetary-mass object with a differentiated rocky body, making it a satellite planet under the geophysical definitions of the term and larger than all known dwarf planets of the Solar System. It lacks any significant atmosphere, hydrosphere, or magnetic field. Its surface gravity is about one-sixth of Earth's at , with Jupiter's moon Io being the only satellite in the Solar System known to have a higher surface gravity and density. The Moon orbits Earth at an average distance of , or about 30 times Earth's diameter. Its gravitational influence is the main driver of Earth's tides and very slowly lengthens Earth's day. The Moon's orbit around Earth has a sidereal period of 27.3 days. During each synodic period ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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