Caloris Planitia 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.
The geology of Mercury is the scientific study of the surface, crust, and interior of the planet Mercury. It emphasizes the composition, structure, history, and physical processes that shape the planet. It is analogous to the field of terrestrial geology. In planetary science, the term geology is used in its broadest sense to mean the study of the solid parts of planets and moons. The term incorporates aspects of geophysics, geochemistry, mineralogy, geodesy, and cartography.
The Tolstoj quadrangle in the equatorial region of Mercury runs from 144 to 216° longitude and -25 to 25° latitude. It was provisionally called "Tir", but renamed after Leo Tolstoy by the International Astronomical Union in 1976. Also called Phaethontias.
The Shakespeare quadrangle is a region of Mercury running from 90 to 180° longitude and 20 to 70° latitude. It is also called Caduceata.
Mozart is a crater on Mercury, named by the IAU in 1976 after Austrian composer Wolfgang Amadeus Mozart.
Eminescu is a peak ring crater on Mercury 125 kilometers (78 mi) in diameter. Since there are very few later craters superposed on it, Eminescu appears to be a young crater formed around one billion years ago. It has a transitional morphology between larger more complex impact basins like Raditladi and smaller simpler central peak craters.
Apollodorus is an impact crater on Mercury. Its unusual appearance, with radiating dark troughs, led to a nickname of "the Spider" by scientists before its official name was decided. Apollodorus is located near the center of Pantheon Fossae, which is a system of radial grabens situated in the inner part of the Caloris basin. The floor, rim and walls of Apollodorus expose a low reflectance material (LRM) excavated during the impact from beneath the light volcanic plains, which cover the central part of the Caloris.
Cunningham is a young crater on the western floor of the Caloris Basin, on Mercury. It is surrounded by a bright ray system.
Sander is a crater on Mercury within Caloris Basin. It has dark walls and bright patches on its floor. Unlike the rays of Bashō crater, the bright areas are not believed to be immature, but they are inherently bright. It is named after the German photographer August Sander (1876–1964).
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.
Amaral is a crater on the planet Mercury. With its smooth floor, surrounding ejecta, and small secondary craters, it appears noticeably younger than the heavily cratered surface around it. Along with a smooth crater floor, Amaral also has a central peak. Bright material on this peak is of particular interest as it appears to have an unusual color. In color-enhanced images, the central peak of Amaral appears as a bright blue color in striking contrast to the otherwise orange tones of surface material nearby. The different color of the central peak likely indicates rocks with different chemical composition from those on the neighboring surface.
Raditladi is a large impact crater on Mercury with a diameter of 263 km. Inside its peak ring there is a system of concentric extensional troughs (graben), which are rare surface features on Mercury. The floor of Raditladi is partially covered by relatively light smooth plains, which are thought to be a product of the effusive volcanism. The troughs may also have resulted from volcanic processes under the floor of Raditladi. The basin is relatively young, probably younger than one billion years, with only a few small impact craters on its floor and with well-preserved basin walls and peak-ring structure. It is one of 110 peak ring basins on Mercury.
Berkel is a crater on the planet Mercury. Its name was approved by the IAU on July 9, 2009. It was named after the modernist painter Sabri Berkel.
Nāwahī is a crater on Mercury. Nāwahī crater is located within the large Caloris basin, near the western rim. The unusual dark material creating a halo around Nāwahī makes this crater of special interest, as the dark material likely represents rocks with a different chemical and mineralogical composition than those of the neighboring surface. The crater is named after Hawaiian patriot and painter Joseph Nāwahī.
Rachmaninoff is an impact crater on Mercury. This basin, first imaged in its entirety during MESSENGER's third Mercury flyby, was quickly identified as a feature of high scientific interest, because of its fresh appearance, its distinctively colored interior plains, and the extensional troughs on its floor. The morphology of Rachmaninoff is similar to that of Raditladi, which is one of the youngest impact basins on Mercury. The age of Raditladi is estimated at one billion years. Rachmaninoff appears to be only slightly older.
Derain is a crater on Mercury named after André Derain, a French artist, painter, sculptor and co-founder of Fauvism with Henri Matisse. It has uncommonly dark material within and surrounding the crater. The material is darker than the neighboring terrain such that this crater is easily identified even in a distant global image of Mercury. The dark halo may be material with a mineralogical composition different from the majority of Mercury's visible surface. Craters with similar dark material on or near their rims were seen on the floor of the Caloris basin during MESSENGER’s first flyby.
Bartók is a crater on Mercury. Its name was adopted by the International Astronomical Union (IAU) in 1979. Bartók is named for the Hungarian composer Béla Bartók, who lived from 1881 to 1945.
Balanchine is a crater on the planet Mercury. It possesses a ray system of slightly bluish rays. These rays inspired the name of the crater due to their similarity to the tutu in George Balanchine's Serenade.
Alver is a crater on Mercury. It has a diameter of 151.49 kilometers. Its name was adopted by the International Astronomical Union (IAU) on March 15, 2013. Alver is named for the Estonian poet Betti Alver.
Hollows are a landform on the planet Mercury, discovered during the MESSENGER mission that orbited the planet from 2011 to 2015.
Closeup of Atget also from MESSENGER
Atget crater in exaggerated color
