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.
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.
Almost all water on Mars today exists as ice, though it also exists in small quantities as vapor in the atmosphere. What was thought to be low-volume liquid brines in shallow Martian soil, also called recurrent slope lineae, may be grains of flowing sand and dust slipping downhill to make dark streaks. While most water ice is buried, it is exposed at the surface across several locations on Mars. In the mid-latitudes, it is exposed by impact craters, steep scarps and gullies. Additionally, water ice is also visible at the surface at the north polar ice cap. Abundant water ice is also present beneath the permanent carbon dioxide ice cap at the Martian south pole. More than 5 million km3 of ice have been detected at or near the surface of Mars, enough to cover the whole planet to a depth of 35 meters (115 ft). Even more ice might be locked away in the deep subsurface.
Hokusai is a rayed impact crater on Mercury, which was discovered in 1991 by ground-based radar observations conducted at Goldstone Observatory. The crater was initially known as feature B. Its appearance was so dissimilar to other impact craters that it was once thought to be a shield volcano. However improved radar images by the Arecibo Observatory obtained later in 2000–2005 clearly showed that feature B is an impact crater with an extensive ray system. The bright appearance of rays in the radio images indicates that the crater is geologically young; fresh impact ejecta has a rough surface, which leads to strong scattering of radio waves.
Debussy is a rayed impact crater on Mercury, which was discovered in 1969 by low resolution ground-based radar observations obtained by the Goldstone Observatory. Later in 1990–2005 it was imaged in more detail by the Arecibo Observatory. The crater was initially known as the feature A. The bright appearance of rays in the radar images indicates that the crater is geologically young, because fresh and rough surfaces of young impact craters are good scatterers of radio waves.
Despréz is a crater on Mercury with a diameter of 47.05 kilometers. Its name was adopted by the International Astronomical Union (IAU) in 1979. Despréz is named for the French composer Josquin des Prez, who lived from 1440 to 1521.
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.
Sapkota is a crater on Mercury, located near the north pole. It was named by the IAU in 2015, after Nepalese poet Mahananda Sapkota.
Laxness is a crater on Mercury, located near the north pole. It was named by the IAU in 2013, after Icelandic writer Halldór Laxness.
Fuller is a crater on Mercury, located near the north pole. It was named by the IAU in 2013, after American engineer and architect Richard Buckminster Fuller.
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.
Gordimer is a crater on Mercury, near the north pole. Its name was adopted by the International Astronomical Union (IAU) in 2019, after the South African writer Nadine Gordimer.
Remarque is a crater on Mercury. Its name was adopted by the International Astronomical Union (IAU) on December 16, 2013. Remarque is named for the German author Erich Maria Remarque.
Petronius is a crater on Mercury. It has a diameter of 36 kilometres. Its name was adopted by the International Astronomical Union (IAU) on the August 6, 2012. Petronius is named for the Roman author Petronius.
Morrison is a crater on Mercury. Its name was adopted by the International Astronomical Union in September 2022. Morrison is named for the American author Toni Morrison, who lived from 1931 to 2019.
