Venus crescent phase about one month before or after inferior conjunction. Venus fades to about magnitude −3 when it is backlit by the Sun. The planet is bright enough to be seen in a clear midday sky and is more easily visible when the Sun is low on the horizon or setting. As an inferior planet, it always lies within about 47° of the Sun. Venus "overtakes" Earth every 584 days as it orbits the Sun. As it does so, it changes from the "Evening Star", visible after sunset, to the "Morning Star", visible before sunrise. Although Mercury, the other inferior
Tunnel in the Sky Tunnel in the Sky Tunnel in the Sky is a juvenile science fiction novel by American writer Robert A. Heinlein, published in 1955 by Scribner's as one of the Heinlein juveniles. The story describes a group of students sent on a survival test to an uninhabited planet, who soon realise they are stranded there. The themes of the work include the difficulties of growing up and the nature of man as a social animal. The novel is set in the future, when Malthusian overpopulation on Earth has been averted by the invention of teleportation, called the "Ramsbotham jump", which is