Planets of the Hainish Cycle third planet of our solar system. Terrans are descendents of colonists from Hain. At some unspecified date, Terrans join the "League of All Worlds", which includes the Cetians and other peoples of Hainish descent. In "The Left Hand of Darkness", it is said that 'Hainish Normal' people were placed among Terra's own proto-hominid autochthones by the ancient Hainish 'colonizers'. After that initial contact with Hainish civilization Terra experiences two more cycles of isolation followed by the restoration of extraterrestrial contact and community with other worlds. The second period of contact with the interstellar Hainish community is the background for "The
Solar System largely of materials with lower melting points. The boundary in the Solar System beyond which those volatile substances could condense is known as the frost line, and it lies at roughly 5 AU from the Sun. The objects of the inner Solar System are composed mostly of rock, the collective name for compounds with high melting points, such as silicates, iron or nickel, that remained solid under almost all conditions in the protoplanetary nebula. Jupiter and Saturn are composed mainly of gases, the astronomical term for materials with extremely low melting points and high vapour pressure, such as hydrogen, helium,