Rainbow (Noon Universe)

Rainbow (Радуга, pronounced: Raduga) is a fictional planet described in Far Rainbow by Arkady and Boris Strugatsky. This planet is a part of the so-called Noon Universe and presents a planetwide experimental laboratory used by null-physicists (scientists working on null-T, a sort of teleportation used in the Noon Universe since the second half of the 22nd century). It isn't clear when it was discovered but, presumably, somewhere between 2146 and 2154 AD.

Rainbow is a very comfortable planet with a moderate climate, a calm atmosphere, little seismic activity and a rather phlegmatic native fauna. There is only one continent (in the Northern hemisphere) and some small archipelagos (in the South one, which is covered with an ocean). Remarkably, the coastal line between the southern ocean and the northern continent roughly coincides with the equator.

Rainbow didn't have a native intelligent species until it was discovered by Earth's explorers. Shortly after that it was "inhabited" by null-physicists, scientists studying the null-T (teleportation). The null-T was an urgent and promising problem in the 50s but it was also quite dangerous (see below, "The Wave") so the government of Earth decided to move all null-physicists to another planet where they could carry out their experiments without endangering the rest of humanity.

Rainbow is a unique laboratory-planet where all economics, industrial and agrarian sectors are aimed to support 120 scientists who work on a solution of the transport theorem. Together (null-physicists, biologists, children, tourists, null-T testers) the total population of the planet's barely ever reached 300 people. The whole planet is governed by the Council, consisting of the leading scientists and some administrators including the general director, Matvei Vyazanitsyn.

Only one town named simply Capital (the permanent residence of the Council) exists on Rainbow; all other settlements are either small villages or just observatories.

...
Wikipedia