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
The Empty Planet them a newspaper so they can quickly learn the human language. They reveal the strange image is a countdown. They demand the air and the sun, saying that if it is not given to them by the end of the countdown the human race will not return. Rani realises that they don't mean 'sun and air' but 'son and heir'. It turns out that Gavin's father was an alien king, who has now died. The robots have come to take Gavin to their planet and sent the news he is a prince in the energy trace, but Gavin never received