Planet smallest known planet is PSR B1257+12A, one of the first extrasolar planets discovered, which was found in 1992 in orbit around a pulsar. Its mass is roughly half that of the planet Mercury. The smallest known planet orbiting a main-sequence star other than the Sun is Kepler-37b, with a mass (and radius) slightly higher than that of the Moon. Every planet began its existence in an entirely fluid state; in early formation, the denser, heavier materials sank to the centre, leaving the lighter materials near the surface. Each therefore has a differentiated interior consisting of a dense planetary core surrounded
Terminus (planet) Terminus (planet) Terminus is a fictional planet at the edge of the Galaxy in Isaac Asimov's "Foundation Series", home of the Foundation (later capital of the Foundation Federation). Terminus is the sole planet orbiting an isolated star. Its nearest inhabited neighbor is Anacreon, 8 parsecs (26 light years) away, and it lies approximately 10,000 parsecs from the capital of the First Galactic Empire, Trantor, near the galactic center. There are almost no visible stars in its sky, only the huge lens of the Milky Way Galaxy. The nearby stars of the Province of Anacreon are known as "The Diamonds", with