Planet the Drake equation, which estimates the number of intelligent, communicating civilizations that exist in the Milky Way. There are exoplanets that are much closer to their parent star than any planet in the Solar System is to the Sun, and there are also exoplanets that are much farther from their star. Mercury, the closest planet to the Sun at 0.4 AU, takes 88 days for an orbit, but the shortest known orbits for exoplanets take only a few hours, e.g. Kepler-70b. The Kepler-11 system has five of its planets in shorter orbits than Mercury's, all of them much more massive
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