An Etymological Dictionary of Astronomy and Astrophysics

The extension of the → black hole concept in a → space-time with → dimensions higher than 4. Theoretically, it is possible to extend the 4D black hole with S² horizon into the fifth dimension producing a hypercylindrical black hole S²× R. Black strings are unstable; it is not yet well understood whether they end up as black holes or different objects.

See also: → black; → string.