# Lorentz Symmetry

Quick question about Lorentz symmetry. From the wiki page

the feature of nature that says experimental results are independent of the orientation or the boost velocity of the laboratory through space.

I'm slightly confused. Obviously four-momentum is not Lorentz invariant. It's value depends on our frame of reference. But it is an observable, so shouldn't we be able to measure it in an experiment and thus find different values in different frames?

• Ah okay I see. I understand what you're saying. My only confusion now is how four-momentum relative to a lab is related to the four-vector $p^\mu$ we use in relativistic mechanics. – Okazaki Aug 7 '15 at 19:53