Mercury is the first planet from the Sun and the smallest in the Solar System. In English, it is named after the Roman god Mercurius (Mercury), god of commerce and communication, and the messenger of the gods. Mercury is classified as a terrestrial planet, with roughly the same surface gravity as Mars. The surface of Mercury is heavily cratered, as a result of countless impact events that have accumulated over billions of years. Its largest crater, Caloris Planitia, has a diameter of 1,550 km (960 mi) and one-third the diameter of the planet. Similarly to the Earth's Moon, Mercury's surface displays an expansive rupes system generated from thrust faults and bright ray systems formed by impact event remnants.
MESSENGER was a NASA robotic space probe that orbited the planet Mercury between 2011 and 2015, studying Mercury's chemical composition, geology, and magnetic field. The name is a backronym for "Mercury Surface, Space Environment, Geochemistry, and Ranging", and a reference to the messenger god Mercury from Roman mythology.
Shackleton is an impact crater that lies at the lunar south pole. The peaks along the crater's rim are exposed to almost continual sunlight, while the interior is perpetually in shadow. The low-temperature interior of this crater functions as a cold trap that may capture and freeze volatiles shed during comet impacts on the Moon. Measurements by the Lunar Prospector spacecraft showed higher than normal amounts of hydrogen within the crater, which may indicate the presence of water ice. The crater is named after Antarctic explorer Ernest Shackleton.
Lunar water is water that is present on the Moon. Diffuse water molecules in low concentrations can persist at the Moon's sunlit surface, as discovered by the SOFIA observatory in 2020. Gradually, water vapor is decomposed by sunlight, leaving hydrogen and oxygen lost to outer space. Scientists have found water ice in the cold, permanently shadowed craters at the Moon's poles. Water molecules are also present in the extremely thin lunar atmosphere.
Chao Meng-Fu is a 167 km (104 mi) diameter crater on Mercury named after the Chinese painter and calligrapher Zhao Mengfu (1254–1322). Due to its location near Mercury's south pole and the planet's small axial tilt, an estimated 40% of the crater lies in permanent shadow. This combined with bright radar echoes from the location of the crater leads scientists to suspect that it may shelter large quantities of ice protected against sublimation into the near-vacuum by the constant −171 °C (−276 °F) temperatures.
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.
A cold trap is a concept in planetary sciences that describes an area cold enough to freeze (trap) volatiles. Cold-traps can exist on the surfaces of airless bodies or in the upper layers of an adiabatic atmosphere. On airless bodies, the ices trapped inside cold-traps can potentially remain there for geologic time periods, allowing us a glimpse into the primordial solar system. In adiabatic atmospheres, cold-traps prevent volatiles from escaping the atmosphere into space.
The Mare Boreum quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Mare Boreum quadrangle is also referred to as MC-1. Its name derives from an older name for a feature that is now called Planum Boreum, a large plain surrounding the polar cap.
The Mare Australe quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Mare Australe quadrangle is also referred to as MC-30. The quadrangle covers all the area of Mars south of 65°, including the South polar ice cap, and its surrounding area. The quadrangle's name derives from an older name for a feature that is now called Planum Australe, a large plain surrounding the polar cap. The Mars polar lander crash landed in this region.
A permanently shadowed crater is a depression on a body in the Solar System within which lies a point that is always in darkness.
Kandinsky is a deep crater on Mercury, located near the planet's north pole. It was named by the IAU in 2012 for Russian painter Wassily Kandinsky.
Tolkien is one of the northernmost craters on Mercury, located in the Borealis quadrangle at 88.82 N, 211.08 W. It is 50 km in diameter. It was named after the South African born British writer J. R. R. Tolkien. The name was approved by IAU's Working Group for Planetary System Nomenclature on August 6, 2012. Since Tolkien is very close to the north pole, and Mercury has almost no axial tilt, Tolkien receives very little sunlight. S band radar data from the Arecibo Observatory collected between 1999 and 2005 indicates a radar-bright area covers the entire floor of Tolkien, which is probably indicative of a water ice deposit.
Carolan is a crater on Mercury. Its name was suggested by an Irishman, Fergal Donnelly, and two Americans, Joseph Brusseau and Deane Morrison, in a naming contest which was eventually adopted by the International Astronomical Union (IAU) on 2015. Carolan is named for the Irish composer and performer Turlough O'Carolan, who lived from 1670 to 1738 C.E. The craters Kulthum, Enheduanna, Karsh, and Rivera were also named as part of the contest.
Vonnegut is a crater on Mercury, near the north pole. It was named by the IAU in 2017 after the American author Kurt Vonnegut. Part of Vonnegut's 1959 novel The Sirens of Titan takes place on Mercury. The crater was referred to as e5 in scientific literature prior to naming.
Yoshikawa is a crater on Mercury, near the north pole. It was named by the IAU in 2012 after the Japanese novelist Eiji Yoshikawa.
Tryggvadóttir is a crater on Mercury. The north pole of Mercury is located next to its northern rim. It was named by the IAU in 2012 after the Icelandic artist Nína Tryggvadóttir.
Chesterton is a crater on Mercury, near the north pole. Its name was adopted by the International Astronomical Union in 2012, after the English author G. K. Chesterton.
Yamada is a crater on Mercury. It has a diameter of 17.1 kilometres. Its name was adopted by the International Astronomical Union (IAU) on November 4, 2015. Yamada is named for the Japanese composer and conductor Kosaku Yamada. The crater was referred to as n5 in scientific literature prior to naming.
Bunin is a crater on Mercury, located near the north pole. Its name was adopted by the International Astronomical Union (IAU) in 2019. It is named for the Russian author Ivan Bunin. The crater was referred to as l7 in scientific literature prior to naming.
Josetsu is a crater on Mercury, located near the north pole. Its name was adopted by the International Astronomical Union (IAU) in 2019. It is named for the Japanese painter Taikō Josetsu. The crater was referred to as o7 in scientific literature prior to naming.
