Smaller planets than Earth, Romulus and Remus measure 91 percent of Earth’s diameter and 75 percent of its mass. Gravitational attraction at the surfaces pull with 87 percent of the Earth’s force. The twin planets are similar in many respects. An oxygen-nitrogen atmosphere surrounds both planets and oceans cover a majority of their surfaces. Both planets teem with highly complex forms of life, though colonization by Humans is permitted on Romulus only.
Dry land covers 29 percent of the surface of Romulus, giving the planet a total land area 83 percent as large as Earth’s. Oceans divide the land into eleven small continents distributed on the planet’s surface in three groups. Because Humans have lived on Romulus for a relatively short time, several of the continents remain as yet unnamed.