Phobos Ridge Mars, the fourth planet of the Solar System. Phobos Ridge Phobos Ridge () is a rocky ridge of sandstones and shales forming the west side of Mars Glacier in the southeast corner of Alexander Island, Antarctica. The coast in this vicinity was first seen from the air by Lincoln Ellsworth on November 23, 1935, and roughly mapped from photos obtained on that flight by W.L.G. Joerg. This ridge was first surveyed in 1949 by the Falkland Islands Dependencies Survey (FIDS) and named by the United Kingdom Antarctic Place-Names Committee (UK-APC) for its association with adjacent Mars Glacier, Phobos being the
Ice planet Ice planet An ice planet is a theoretical type of exoplanet with an icy surface of volatiles such as water, ammonia, and methane. Ice planets consist of a global cryosphere. They are bigger versions of the small icy worlds of the Solar System, which includes the moons Europa, Enceladus, and Triton, the dwarf planets Pluto and Eris, and many other small Solar System bodies such as comets. Ice planets usually appear nearly white with geometric albedos of more than 0.9. An ice planet's surface can be composed of water, methane, ammonia, carbon dioxide (known as "dry ice"), carbon monoxide, and