Mercury (planet) Mercury (planet) Mercury is the smallest and innermost planet in the Solar System. Its orbital period around the Sun of 87.97 days is the shortest of all the planets in the Solar System. It is named after the Roman deity Mercury, the messenger of the gods. Like Venus, Mercury orbits the Sun within Earth's orbit as an "inferior planet", and never exceeds 28° away from the Sun. When viewed from Earth, this proximity to the Sun means the planet can only be seen near the western or eastern horizon during the early evening or early morning. At this time it
The Hitchhiker's Guide to the Galaxy Tertiary to Hexagonal Phases nods to the radio series such as a reference to Brontitall and the bird people from the Secondary Phase that were never put into the novels. The episode opens with a Grebulon spaceship suffering an accident, and losing nearly all records of what it is and what it should be doing, along with the crew's memories of why. Based on what little remains of their orders, they land on the tenth planet from the Sun, and start to 'monitor' Earth. After a year's travelling Arthur has returned to the co-ordinates ZZ9 plural Z alpha—where he is expecting to find Earth,