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27-575: Promontorium Heraclides is a raised mountainous cape situated in Mare Imbrium on the near side of the Moon . Its selenographic coordinates are 40.3° N, 33.2° W and it is 50 km in diameter. It marks the western edge of the bay of Sinus Iridum . Promontorium Heraclides is named after Heraclides Ponticus , a Greek philosopher and astronomer. The Soviet lunar probe Luna 17 landed about 30 km from Promontorium Heraclides on November 17, 1970. The land form

54-438: A blanket of debris, which thins at the outermost regions. Ejecta features are classified based on their distance from the impact crater, the appearance of the ejected material, and the geomorphological characteristics of the terrain. Some common ejecta features include ejecta blankets, radial and concentric ejecta patterns, and secondary craters. Ejecta Blankets: Ejecta blankets are the continuous layer of debris that surrounds

81-618: A map of the Moon that names Mare Imbrium "Regio Magna Orientalis" (the Large Eastern Region). Michael van Langren 's 1645 map named it "Mare Austriacum" (the Austrian Sea). Mare Imbrium is visible to the naked eye from Earth. In the traditional ' Man in the Moon ' image seen on the Moon in Western folklore, Mare Imbrium forms the man's right eye. On 17 November 1970 at 03:47 Universal Time,

108-466: A proto-planet from the asteroid belt collided with the Moon during the Late Heavy Bombardment . The impact is dated to approximately 3922 ± 12 million years ago, based on radiometric dating techniques. Ejecta from the impact covers large areas of the near side of the Moon. With a diameter of 1145 km, Mare Imbrium is second only to Oceanus Procellarum in size among the maria, and it

135-559: A volcano's vent, causing heat and pressure to build up to an extreme with no way to escape. When the blockage breaks and cannot sustain itself any longer, a more violent eruption occurs, which allows materials to be ejected out of the volcano. Ejecta can consist of: These particles may vary in size; tephra can range from ash (< 1 / 10 inch [0.25 cm]) or lapilli (little stones from 1 / 10 to 2 + 1 ⁄ 2 inches or 0.25 to 6.35 centimetres) to volcanic bombs (>2.5 inches [6.4 cm]). In planetary geology ,

162-537: Is a vast lava plain within the Imbrium Basin on the Moon and is one of the larger craters in the Solar System . The Imbrium Basin formed from the collision of a proto-planet during the Late Heavy Bombardment . Basaltic lava later flooded the giant crater to form the flat volcanic plain seen today. The basin's age has been estimated using uranium–lead dating methods to approximately 3.9 billion years ago, and

189-498: Is compositionally distinct from the Apollo and Luna landing sites. Ejecta Typically in volcanology , ejecta is a result of explosive eruptions . In an explosive eruption, large amounts of gas are dissolved in extremely viscous lava; this lava froths to the surface until the material is expelled rapidly due to the trapped pressure. Sometimes in such an event a lava plug or volcanic neck forms from lava that solidifies inside

216-411: Is depicted as the face of a woman looking across Sinus Iridum in a 1679 lunar map by Giovanni Domenico Cassini ; this depiction, of disputed origin, is known as the "Moon Maiden". This article related to the Moon is a stub . You can help Misplaced Pages by expanding it . Mare Imbrium Mare Imbrium / ˈ ɪ m b r i ə m / ( Latin imbrium , the " Sea of Showers " or " Sea of Rains ")

243-550: Is submerged under the mare's basalt, resulting in only isolated peaks remaining in some areas, such as Mons Pico and Mons La Hire . Numerous estimates of the depth of the mare material have been made using various methods. These include analyses of gravity, seismic, and radar data; studies of craters partially filled with basalt and those that have completely penetrated the mare; and comparisons of lunar basins filled with mare deposits to unfilled basins. These studies have yielded depth estimates ranging from 2 km to 5 km in

270-598: Is the largest mare associated with an impact basin. The Imbrium Basin is surrounded by three concentric rings of mountains, uplifted by the colossal impact event that excavated it. The outermost ring of mountains has a diameter of 1300 km and is divided into several different ranges; the Montes Carpatus to the south, the Montes Apenninus to the southeast, and the Montes Caucasus to the east. At their highest,

297-530: The Apennine Mountains . Commander David Scott and Lunar Module Pilot James Irwin spent three days on the surface of the Moon, including 18½ hours outside the spacecraft on lunar extra-vehicular activity . Command Module Pilot Alfred Worden remained in orbit and acquired hundreds of high-resolution photographs of Mare Imbrium (and other regions of the Moon) as well as other types of scientific data. The crew on

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324-417: The Moon's entire lithosphere . At the region of the Moon's surface exactly opposite Imbrium Basin, there is a region of chaotic terrain (the crater Van de Graaff ) which is thought to have been formed when the seismic waves of the impact were focused there after travelling through the Moon's interior. Mare Imbrium is about 750 miles (1,210 km) wide. A mass concentration (mascon), or gravitational high,

351-472: The Moon's surface by large projectiles blasted out of the basin at low angles, causing them to skim across the lunar surface ploughing out these features. The sculpture pattern was first identified by Grove Karl Gilbert in 1893. Furthermore, a Moon-wide pattern of faults which run both radial to and concentric to the Imbrium basin were thought to have been formed by the Imbrium impact; the event literally shattered

378-503: The Soviet spacecraft Luna 17 made a soft landing in the mare, at latitude 38.28 N, and longitude 35.00 W. Luna 17 carried Lunokhod 1 , the first robotic rover to be deployed on the Moon or any extraterrestrial body. Lunokhod 1, a remote-controlled rover, was successfully deployed and undertook a mission lasting several months. In 1971, the crewed Apollo 15 mission landed in the southeastern region of Mare Imbrium, between Hadley Rille and

405-500: The Yutu rover 7 hours and 24 minutes later. Chang'e 3 mission attempted to perform the first direct measurement of the structure and depth of the lunar soil down to a depth of 30 m (98 ft), and investigate the lunar crust structure down to several hundred meters deep. The rover's ground penetrating radar found evidence of at least nine distinct rock layers , indicating that the area had surprisingly complex geological processes and

432-457: The central part of the mare. It is thought that the original crater left by the Imbrium impact was as much as 100 km deep, but that the floor of the basin bounced back upwards immediately afterwards. Surrounding the Imbrium Basin is a region blanketed by ejecta from the impact, extending roughly 800 km outward. Also encircling the basin is a pattern of radial grooves called the "Imbrium Sculpture", which have been interpreted as furrows cut in

459-407: The diameter of the impactor has been estimated to be 250 ± 25 km. The Moon's maria (plural of mare ) have fewer features than other areas of the Moon because molten lava pooled in the craters and formed a relatively smooth surface. Mare Imbrium is not as flat as it would have originally been when it first formed as a result of later events that have altered its surface. Mare Imbrium formed when

486-469: The impact crater, thinning outwards from the crater's rim. The composition of the ejecta blanket can provide valuable information about the geological composition of the impacted surface and the projectile that caused the impact. The distribution and morphology of the ejecta blanket can also provide insight into the impact angle and the dynamics of the ejecta emplacement process. Radial and Concentric Ejecta Patterns: Radial ejecta patterns are characterized by

513-496: The mare may be "The Shrine of Hecate "; Plutarch records that the Ancient Greeks gave this name to the largest of the "hollows and deeps" on the Moon, believing it to be the place where the souls of the deceased were tormented. Ewen A. Whitaker argues that this likely refers to Mare Imbrium, "the largest regular-shaped dark area unbroken by bright patches" that can be seen with the naked eye. Around 1600, William Gilbert made

540-535: The outer ring of mountains rise more than 5 km above the surface of Mare Imbrium. The ring mountains are not as well developed to the north and west, and it appears they were simply not raised as high in these regions by the Imbrium impact. The middle ring of mountains forms the Montes Alpes and Montes Archimedes . The innermost ring, with a diameter of 650 km, is defined by Montes Recti , Montes Teneriffe , and possibly Montes Spitzbergen . Much of this ring

567-432: The outward distribution of ejecta from the crater in a series of rays or streaks. These rays are often more prominent in craters formed on solid surfaces, such as the Moon or Mercury. Concentric ejecta patterns are characterized by the presence of multiple, circular layers of ejecta surrounding the impact crater. These patterns are commonly observed on icy surfaces, such as the moons of Jupiter and Saturn, and are indicative of

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594-434: The presence of subsurface volatiles, like water or other ices. If enough ejecta are deposited around an impact crater , it can form an ejecta blanket ; this blanket is full of dust and debris that originated from the initial impact. The size of this impact crater along with the ejecta blanket can be used to determine the size and intensity of the impacting object. On earth, these ejecta blankets can be analyzed to determine

621-504: The rille wall. On 17 March 2013, an object hit the lunar surface in Mare Imbrium and exploded in a flash of apparent magnitude 4. The resulting crater was 18 meters wide. This was the brightest impact recorded since NASA's lunar impact team began monitoring in 2005. Chang'e 3 landed on 14 December 2013 on Mare Imbrium, about 40 km south of the 6 km diameter Laplace F crater, at 44.1260°N 19.5014°W. The lander deployed

648-450: The source location of the impact. A lack of impact ejecta around the planet Mars 's surface feature Eden Patera was one of the reasons for suspecting in the 2010s that it is a collapsed volcanic caldera and not an impact crater. In astrophysics or heliophysics , ejecta refers to material expelled in a stellar explosion as in a supernova or in a coronal mass ejection (CME). Beside material launched by humans into space with

675-429: The surface explored the area using the first lunar rover and returned to Earth with 77 kilograms (170 lb) of lunar surface material. Samples were collected from Mons Hadley Delta , believed to be a fault block of pre-Imbrian ( Nectarian or Pre-Nectarian ) lunar crust, including the " Genesis Rock ." This was also the only Apollo mission to visit a lunar rille, and to observe outcrops of lunar bedrock visible in

702-445: The term "ejecta" includes debris ejected during the formation of an impact crater . When an object massive enough hits another object with enough force, it creates a shockwave that spreads out from the impact. The object breaks and excavates into the ground and rock, at the same time spraying material known as impact ejecta. This ejecta is distributed outward from the crater's rim onto the surface as debris; it can be loose material or

729-451: Was identified in the center of Mare Imbrium from Doppler tracking of the five Lunar Orbiter spacecraft in 1968. The Imbrium mascon is the largest on the Moon. It was confirmed and mapped at higher resolution with later orbiters such as Lunar Prospector and GRAIL . Like most of the other maria on the Moon, Mare Imbrium was named by Giovanni Riccioli , whose 1651 nomenclature system has become standardized. The earliest known name for

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