Continent with other islands in the Pacific into one continent called Oceania. This divides the entire land surface of Earth into continents or quasi-continents. The ideal criterion that each continent is a discrete landmass is commonly relaxed due to historical conventions. Of the seven most globally recognized continents, only Antarctica and Australia are completely separated from other continents by the ocean. Several continents are defined not as absolutely distinct bodies but as ""more or less" discrete masses of land". Asia and Africa are joined by the Isthmus of Suez, and North and South America by the Isthmus of Panama. In both
Counter-Earth an updated version of the idea, wherein a spherical Earth must have a more or less balanced distribution of land and water. Mela drew the first map on which the mysterious continent of Earth appears in the unknown half of Earth—our antipodes. This continent he inscribed with the name Antichthones. Philolaus's ideas were all eventually superseded by the modern belief that a spherical Earth rotating on its own axis was one of several spherical planets following the laws of gravity and revolving around a much larger Sun. The idea of a Counter-Earth waned after the heliocentric model of the solar