- Roman ring
A Roman ring, in theoretical
physics , is a configuration ofwormhole s where for each individual wormhole thetime difference across its mouths is such that it may not allow aclosed timelike curve (CTC), or 'closed-time loop'. If these wormholes and their mouths are arranged in a suitable configuration, a closed time loop will be again possible.For example, an
Earth -Moon wormhole whose far end is 0.5 seconds in the "past" will not violatecausality , since information sent to the far end via the wormhole and back through normal space will still arrive back on Earth (-0.5 + 1) = 0.5 seconds after it was transmitted; but an additional wormhole in the other direction will allow information to arrive back on Earth 1 second "before" it was transmitted.Semiclassical approaches to incorporating quantum effects into general relativity seem to show that the
chronology protection conjecture postulated by physicistStephen Hawking fails to prevent the formation of such rings, although some experts such asMatt Visser feel that there are reasons to think the semiclassical approach is unreliable here, and that a full theory ofquantum gravity will likely uphold chronology protection.References
*
*
Wikimedia Foundation. 2010.