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
Return to the Lost Planet Return to the Lost Planet Return to the Lost Planet is a 1954 juvenile science fiction novel by Angus MacVicar, published by Burke, London. It is the second of the Lost Planet series, which was adapted for radio and television. There are six novels in the Lost Planet series: "The Lost Planet" (1953), "Return to the Lost Planet" (1954), "Secret of the Lost Planet" (1955), "Red Fire on the Lost Planet" (1959), "Peril on the Lost Planet" (1960) and "Space Agent from the Lost Planet". It was the first science fiction series ever translated into Hebrew and had considerable impact