“What we observe is not nature itself, but nature exposed to our method of questioning.” –Werner Heisenberg
You might think there are few sacred quantities when it comes to matter: properties that are so fundamentally inherent that even the weirdness of quantum mechanics can’t touch them.
But the quantum nature of the Universe will have none of our prejudices, and will simply do what it does whether we like it or not. And that means, puzzlingly enough, that it’s physically impossible to know, exactly, what the mass of any one particle actually is!How does this work? Go read the whole thing and find out!