particles traveling backwards in time

electrogluon

Recently I heard that when a particle travels back in time it carries the opposite force to it travelling forward in time
For example if an electron travels back in time then it has positive charge.
I need to know if this is true or not and if so does if affect all types of particle such as;
Hadrons,leptons,baryons etc

DrChinese

More or less, yes, this is accurate. An electron going backwards in time would have a positive charge. A proton going backward in time has a negative charge. Their mass is still positive. But most of the other property (charge, parity, etc.) values would be reversed.

electrogluon

so does this apply to the particles involved in the Casimir effect?

DrChinese

Yes, the same basic rules apply to virtual particles.

electrogluon

thanks i needed reassuring on it