Stable Time Loop: Difference between revisions

* You never thought you'd see it, but some non-trivial physicists are [http://www.nytimes.com/2009/10/13/science/space/13lhc.html?_r=2 wondering] [http://io9.com/5380647/is-the-large-hadron-collider-being-sabotaged-from-the-future aloud] whether the future is [[Set Right What Once Went Wrong|actively trying to scuttle]] the LHC research project. The string of mechanical difficulties, they say, may be more than mere chance: Whether through [future] human intervention or the universe itself exercising some form of upstream-acting [[Ontological Inertia]], the future is trying to make sure we don't mess with Higgs Bosons. Loopy? Literally. Crazy? Probably. Impossible? Well...

** [[Futurama|Mumbo? Perhaps. Jumbo? Perhaps not!]]

* In terms of the theory of relativity, time travel would take the appearance of a ''closed timelike curve'', which is a series of events returning to its starting point - such as time travel returns to the past. That leads to the inevitable paradoxes, but some solutions claim that if time travel is possible at all, it's only possible in a stable form: the only form of time travel possible generates a Stable Time Loop.

** While that may seem supremely useless - what good is a time machine if it can't change anything? - that's not really true. A computer that could only build Stable Time Loops could run algorithms like "open time communication channel to 5 minutes into the future, receive answer from future, close channel, check answer (which takes 5 minutes in this example), if correct, send answer over the communication channel that was now just opened, if incorrect send different answer to past over the same communication channel", and then consistency would force the algorithm to return the output to some given puzzle. This is known as Time Loop Logic. Receiving an incorrect answer from the future would cause a paradox, and thus is impossible. Therefore either the answer will never arrive, or you will have created an ontological paradox, fabricating the answer from nowhere. The step of checking the answer is required for the algorithm to work.

* Older theories of cosmology fiddled with the possibility this universe is a Stable Time Loop. Big Bang leads to Expansion, Contraction, finally the Big Crunch which Big Bangs again and we still have no idea where it all 'originally' came from.

* Some theories of particle physics hold that antiparticles (particles with the opposite charge and parity of a "standard" particle) travel backward through time. It's also widely believed that particle-antiparticle pairs randomly pop into existence from the [[wikipedia:Quantum foam|Quantum Foam]], and then feel their mutual attraction and annihilate each other moments later. It's also possible to see this as a single particle traveling in a loop through time: Forward as a regular particle to annihilate with its antiparticle, then backward as its antiparticle to annihilate with its standard particle, and repeat.

 

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