Mercury (planet) diagram on the right illustrates the effects of the eccentricity, showing Mercury's orbit overlaid with a circular orbit having the same semi-major axis. Mercury's higher velocity when it is near perihelion is clear from the greater distance it covers in each 5-day interval. In the diagram the varying distance of Mercury to the Sun is represented by the size of the planet, which is inversely proportional to Mercury's distance from the Sun. This varying distance to the Sun leads to Mercury's surface being flexed by tidal bulges raised by the Sun that are about 17 times stronger than the Moon's
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