ps3

the author of the article said "virtual particles can travel slower or faster than light,forwards and bavkwards in time,however they are virtual.

i saw a video on youtube where a guy is trying to build a time machine. http://en.wikipedia.org/wiki/Ronald_Mallett swansont have you read the two links i provided?

anything going back in time would be paradoxical right?

so not something actully physical or really happening in the universe?

how come he says they are not paradoxical?

have you heard of his model?

what is that stenger is talking about then?

did you read the links i provided? what is it that the writer is talking about? because if these particles are able to do this,they would violate laws and causality and see weird paradoxes.

have these two links where the writer says that quantum particle's do in fact travel back in time,is this true? or i misread them? http://www.colorado.edu/philosophy/vstenger/Briefs/QuantumTimeTravel.html http://www.colorado.edu/philosophy/vstenger/void.html

here is where i got my info. http://www.colorado.edu/philosophy/vstenger/Briefs/QuantumTimeTravel.html http://www.colorado.edu/philosophy/vstenger/void.html

what are talking about?? this is different.

ok,i read it,so his "time machine" won't work? also do quantum particle's travel back in time?

In the early 90's a Professor proposed a theory for a "quantum Time machine" http://www.npl.washington.edu/AV/altvw45.html

well,my project is more on time travel.have you heard of yakir aharonov?

im doing a school project on them which has to be done soon.

ya becuase you guys don't give simple answer's like these guys on here.

so just becuase relativity allows something doesnt mean it can work in the universe? so relativty could allow it but not the universe? so the solutions would have to be wrong for there to be no ctc's? or can the solution be right without any ctc's?

would something be wrong if ctc's did not exist? causality would be violated if they existed? what would be proof that ctc's exist?

ive read or been told,im not sure,that QG will probly prevent ctc from forming.

are they physicaly real? what is thought to prevent them?

so virtual particle's don't do any of that sci-fi stuff like a time loop or going back in time sort of thing?

im having trouble because i was told that they travel faster than light,but im all ears though.

why are virtual particle's allowed to travel faster than the speed of light?

need a bit of help till i turn in my paper.

so causality is violated unobservable becuase we cant measure virtual particles? my friend said "While virtual particles can break causality, we can never observe virtual particles, and so we never can observe causality violations. What is a virtual particle? Virtual particles are how we understand that quantum interactions occur. For example, suppose two electrons come along and bump off of each other. One electron experiences the electric field of the other electron. The force between the two electrons is due to exchange of photons. These photons are virtual. Given this, the influence of one electron on another is the result of a sum over all of the virtual photons exchanged---this is the Feynman path integral. While some virtual photons travel faster than the speed of light, some (in fact, many more) photons also travel slower than the speed of light. This means that the net effect is mediated at a speed that respects causality. Summary: While one photon in the interaction may travel faster than the speed of light, the net effect of the interaction requires that one sum over all photons exchanged. Because the probability of a virtual photon traveling slower than the speed of light is MUCH greater than the probability of a virtual photon traveling faster than the speed of light, the net effect means that the information between the two electrons is exchanged in a manner which respects causality''