Virtual Particle Speed: Is It Measurable?

[Maartenc]

I'm reading up on relativity, but it confuses me.
If I observe a virtual particle pop up in empty space, what sort of average speed would that particle have? It cannot depend on my reference frame, because the particle doesn't know about that. Or perhaps it does, as my observation ties it into my system. Or perhaps it is fundamentally impossible to measure the speed of a virtual particle.

 

[weirdoguy]

Read this:
https://www.physicsforums.com/insights/physics-virtual-particles/
https://www.physicsforums.com/insights/misconceptions-virtual-particles/

 

[soarce]

One can not observe (i.e. detect or measure in some way) a virtual particle. Rigorously speaking, as the virtual particles don't need to obey all the physical laws of real particles, we can say that they may have arbitrarily large speeds. I am not sure whether one can speak of virtual particle speed. However, when speaking of the interaction propagation the top limit is the speed of light and as far I know all fundamental interactions propagate by the speed of light.

 

[Maartenc]

Thanks for the answer, and those links are excellent.