Moebius
A moebius was a hypothetical twist in the fabric of space, wherein time becomes a temporal causality loop from which there was no escape.

In 2365, after the crew of the  encountered Captain Picard's counterpart from six hours in the future, Lieutenant Worf suggested that a moebius may have been responsible, although an exotic energy vortex was ultimately determined to be the cause. ()

See also
 Möbius Inversion
 Pogo paradox
 Predestination paradox
 Topological anomaly

External link 
 

de:Möbiusstreifen
Time travel
Celestial objects
Mathematics