Raftworlds are virchworlds with a huge gravitational constant. Inside, the conditions resemble the fictional "Raft" universe from the book by Old Earth Information Age fabulist Stephen Baxter. The billion-strength gravity allows for large regions of breathable air held together by gravity, and stars only a few kilometres across. The raftworlds were the first of a series of simulated universes in which the physical constants of nature were different.
Another of these virchworlds are TGTworlds, worlds in which the strong nuclear force is hundreds or thousands of times stronger. TGT stands for "The Gods Themselves", a book by information age writer Isaac Asimov in which a parallel universe with this property is described.
Raftworlds and TGTworlds were among the first so-called alternate-constant virches created in the early interplanetary age, when Asimov, Baxter and the like were considered great visionaries of space exploration, scientific achievement and the Singularities. These simulations and other similar virtual universes with different physical laws to our own universe remain very popular in the present era.
Text by Loopquanta
Initially published on 15 December 2006.