Terra incognita refer to the hypothesized continent Terra Australis Incognita ("The unknown land of the South"), as seen in the Theatrum Orbis Terrarum map by Abraham Ortelius (1570). During the 19th century "terra incognita" disappeared from maps of the earth, since both the coastlines and the inner parts of the continents had been fully explored. But the bottoms of the seas remain mostly un-mapped, as do many other land surfaces in the solar system. The phrase is now also used metaphorically by various researchers to describe any unexplored subject or field of research. For more history of the terms, see Terra Australis,
Aonia Terra Aonia Terra Aonia Terra is a region in the southern hemisphere of the planet Mars. It is named after a classical albedo feature, the "Bay of the Muses" and its name was approved in 1979, by the International Astronomical Union (IAU) Working Group for Planetary System Nomenclature. It is centered at and covers 3900 km at its broadest extent. It covers latitudes 30 to 81 South and longitudes 60 to 163 W. Aonia Terra is an upland area notable for massive cratering including the large Lowell Crater, parts of the region features small craters, in the plain areas, Thaumasia Fossae