geologia: Mercury (planet)

Evidence: 100 • authority: 72

Mercury is the first planet from the Sun and the smallest in the Solar System. It is a rocky planet with a trace atmosphere and a surface gravity slightly lower than that of Mars. The surface of Mercury is similar to Earth's Moon, being cratered, with an expansive rupes system generated from thrust faults, and bright ray systems, formed by ejecta. Its largest crater, Caloris Planitia, has a diameter of 1,550 km (960 mi), which is about one-third the diameter of the planet (4,880 km or 3,030 mi). Being the most inferior orbiting planet, it always appears close to the Sun in Earth's sky, as either a "morning star" or an "evening star". It is the planet with the highest delta-v required for tr…

Evidence: 45 • authority: 72

Rembrandt is a large impact crater on Mercury. With a diameter of 716 km it is the second-largest impact basin on the planet, after Caloris, and is one of the larger craters in the Solar System. It was discovered by MESSENGER during its second flyby of Mercury on October 6, 2008. The crater is 3.9 billion years old, and was created during the period of Late Heavy Bombardment. The density and size distribution of impact craters along Rembrandt's rim indicate that it is one of the youngest impact basins on Mercury. The crater is named after Dutch painter Rembrandt Harmenszoon van Rijn.

Evidence: 45 • authority: 88

Deformational histories of the massive infill within Sputnik Planitia (Pluto) and Caloris Basin (Mercury) : Implications for BepiColombo data interpretation and the relationship between the parameters which induce tectonic subsidence. Throughout the Solar System, large infilled basins exhibit a variety of infilling processes, encompassing sedimentary mechanisms (i.e. aeolian or aqueous) and upwelling of material from beneath the basin floor (i.e. mantle pluming, cryovolcanism, mud volcanism, springs). This study compares two such basins, Sputnik Planitia (1000 km diameter) on Pluto and Caloris Basin (1500 km diameter) on Mercury, both believed to have been infilled through upwelling from th…

Evidence: — • authority: 72

The Borealis quadrangle is a quadrangle on Mercury surrounding the north pole down to 65° latitude. It was mapped in its entirety by the MESSENGER spacecraft, which orbited the planet from 2008 to 2015, excluding areas of permanent shadow near the north pole. Only approximately 25% of the quadrangle was imaged by the Mariner 10 spacecraft during its flybys in 1974 and 1975. The quadrangle is now called H-1. It contains the Goethe Basin, whose diameter of at least 400 km (250 mi) makes it the sixth-largest impact basin observed on Mariner 10 images(Murray and others, 1974; Boyce and Grolier, 1977; Strom, 1977). The west half of the mapped area (between long 100° and 190° W.) is dominated by…

Evidence: — • authority: 72

The Chicxulub crater is an impact crater buried underneath the Yucatán Peninsula in Mexico. The crater is named after the onshore inland community of Chicxulub Pueblo. It was formed slightly over 66 million years ago when an asteroid, about ten kilometers (six miles) in diameter, struck Earth. The crater is estimated to be two hundred kilometers (120 mi) in diameter and is buried to a depth of about one kilometer (0.6 mi) beneath younger sedimentary rocks. It is one of the largest impact structures on Earth, alongside the much older Sudbury and Vredefort impact structures, and the only one whose peak ring is intact and directly accessible for scientific research. The crater was discovered b…

Evidence: — • authority: 72

Following are the largest impact craters on various worlds of the Solar System. For a full list of named craters, see List of craters in the Solar System. The ratio column compares the crater diameter with the diameter of the impacted celestial body. The maximum crater diameter is 157% of the body diameter (the circumference along a great circle).

Evidence: — • authority: 72

The Caloris group is a set of geologic units on Mercury. McCauley and others have proposed the name “Caloris Group” to include the mappable units created by the impact that formed the Caloris Basin and have formally named four formations within the group, which were first recognized and named informally by Trask and Guest based on imagery from the Mariner 10 spacecraft that flew by Mercury in 1974 and 1975. The extent of the formations within the group have been expanded and refined based on imagery and other data from the MESSENGER spacecraft which orbited Mercury from 2011 to 2015, and imaged parts of the planet that were in shadow at the time of the Mariner 10 encounters. Like the Imbriu…

Evidence: — • authority: 72

Caloris Planitia (also known as the Caloris Basin) is a plain within a large impact basin on Mercury, informally named Caloris, about 1,550 km (960 mi) in diameter. It is one of the largest impact basins in the Solar System. "Calor" is Latin for "heat" and the basin is so-named because the Sun is almost directly overhead every second time Mercury passes perihelion. The crater, discovered in 1974, is surrounded by the Caloris Montes, a ring of mountains approximately 2 km (1.2 mi) tall.

Evidence: — • authority: 80

Shaded relief map of the Caloris Planitia area of Mercury

Evidence: — • authority: 88

A breached cone-like mountain on Caloris Planitia, Mercury: A candidate scoria cone?. IntroductionExplosive volcanism produces diverse pyroclastic landforms, including scoria cones, which on Earth make up ~90% of subaerial volcanoes and form during Strombolian eruptions as steep edifices with slopes near the angle of repose (~30°). Similar features occur on Mars and the Moon but are less common and morphometrically distinct; Martian cones are broader with gentler slopes due to enhanced pyroclast dispersal [1,2].On Mercury, such edifices were long thought absent, with explosive volcanism inferred mainly from diffuse deposits around irregular vents, consistent with models predicting wide disp…

Evidence: — • authority: 92

The distribution and origin of Mercury's crustal magnetization.. Mercury is the only planet other than Earth to possess both a global magnetic field that arises from a core dynamo, and a crustal magnetic field that arises from magnetized rocks. Crustal fields provide unique records of a planet's interior state and evolution because magnetizations depend on the magnetizing field and the magnetic minerals present. A major unresolved issue for Mercury is the relative contributions of present-day (induced) and ancient (remanent) magnetizations-both are expected but are difficult to separate. The former can elucidate variations in crustal iron content and/or magnetic mineral properties, the latt…

Evidence: — • authority: 88

The Evolution of the Caloris Basin Rim, Mercury. Caloris is Mercury’s largest confirmed impact basin and is distinctly asymmetrical in its shape and morphology [1]. This asymmetry has been attributed to a combination of an unusual formation process [2] and/or extensive subsequent modification of the basin interior, rim and exterior [3]. Some regional processes have been identified [4, 5], but while providing further insights, a complete, more detailed explanation of what processes have affected where remains elusive. Understanding this asymmetry will provide a better grasp of basin formation and surface processes on Mercury, helping to untangle the planet’s complex history, and has potentia…