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.
Inhabitants
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.
Apparently, Rainbow was also the last known residence of Camill, the last remaining of "The Devil's Dozen".
Technology
As already stated, Rainbow doesn't possess a native intelligent species, therefore its level of technological development is equal to that of Earth. But, as every normal laboratory, this planet constantly desires for expensive apparatus and measuring devices (e.g. ulmotrons) that can only be produced on Earth. Therefore there is always a shortage on technics because of a slow delivery speed.
Null-T developed partially on Rainbow is a technology of transporting objects of any size in any direction and any distance. It is based on a so-called puncture of the Riemannian fold (прокол римановой складки) and actually goes against everything proclaimed by traditional theories of absolute space, time-space continuum and kappa-space. Nevertheless, such problem has been raised and successfully solved even though at an enormous cost.
During the study of null-T various problems have arisen and been solved. The most desperate was the Wave (see below) that even managed to divide the null-physicists in two fractions: those who wanted to keep paying greater attention to the null-T itself and those who desperately wanted to study the Wave. The second problem solved on Rainbow shortly before it has been abandoned was that any living matter sent to Earth with null-T has arrived there in form of organic cinder. Later on both this problems were solved and in the 70s null-T has already been a norm of life on Earth.
Earth and Rainbow
For some time, Rainbow has been just another Earth's colony but after the null-T problem was raised, it became a home for all scientists working in this direction. The home planet supported its laboratory with apparatus and resources and received new technological know-how in exchange.
The Wave
The Wave is an attribute of null-T. Every time a piece of material is sent through space with null-T two huge fountains of energy and material waste appear on the poles of the planet. They form the so-called "Wave", an enormous kappa-field that appears simultaneously on both poles and moves towards the equator. This Wave looks like a kilometers high black wall with a thin line of blinding light on the crest and is deadly for any kind of living tissue it touches. The scientists name four types of Waves based on their specific characteristics.
Usually the Wave wears off on a half way to the equator. If not, special energy-absorbing machines called charybdis (after mythological Charybdis from Odyssey) are used to lower the potential energy of the Wave thus wearing it off. It is also known that the Wave can disappear itself any moment for no apparent reason.
In 2156 AD Rainbow was devastated by a Wave of a new type later called P-Wave (after Pagawa, one of the leading null-physicists of the time). Nearly all adults who happened to be on the planet (including all scientists), presumably, perished. The only spaceship at that time on the planet, Tariel II (generally piloted by Leonid Gorbovsky), was only capable of evacuating children. No further attempts to reinhabit Rainbow were undertaken.