Why does mass increase with velocity, but electric charge does not?

If you know anything about special relativity, you know that a particle's mass increases with its velocity. An electron gets heavier and heavier as it gets accelerated by particle colliders, as does a proton.

Mass-dependent quantities, like momentum or energy, are also dependent on velocity.

By contrast, electric charge doesn't get affected by a particle's velocity at all. At all. Not at low speeds. Not at 0.9999999999 times the speed of light.

The same goes with a quark's 'charge'. An up quark's up-ness doesn't get more uppity. A down quark remains down, no matter how much Prozac you give it. Also, the quark's 'color', like red, green, or blue, doesn't change. It stays invariant with respect to the speed of the quark.

Why should some quantities get increased with speed, but others not?

I don't know the why, but I do know that a concept called relativistic invariance is involved. So if you friend a physicist on Facebook, you can drop that phrase into the conversation. He'll probably think you're pretty hot for doing so.

Just trying to help you out.

Electric charge is relativistically invariant. Mass is not.

This has something to do with why it's important that we find the Higgs boson.

You've heard it said that "Magnetism = electricity + special relativity"? Yes? Because, after all, the strength of the magnetic field being proportional to an electric charge's speed, that's pretty odd, right? It's one of the things that tipped off Albert Einstein that maybe physicists' understanding of nature wasn't so complete. So he hummed a little bit and drank a little bit of coffee, and out popped the Special Theory of Relativity.

But if you were a physicist, none of this would make you break a sweat. You'd wave your hands and say, "Face, this is trivial. Trivial! Who doesn't know about relativistic invariance?"

Well, me for one. The older I get, the less I seem to know. *sigh*

"So young, and already so unknown." --Wolfgang Pauli

In The City I have found a place that is not a beige box. In The City, I have come to the top of a hill where I live in the shadow of (trees (palms (others))), and I have come to know Lake (Union (Merritt)). I have come here to watch the people walk and walk and hike up and down in the warm (butter (silk (sweet))) sunlight in the shadow of overpasses.

I am (here (there)). I am (here (gone)). I have become an unlikely exile in this (home (not home)). I am not like the others, not a fortunate, sunshine-headed (girl (person (thing)) or a loud Mexican boy. I am not of The City. I am a visitor of The City and Lake (Merritt (Union)). Today I parked by the lake and sat while a man fed fries to the obese seagulls. Today I sat in a cubicle. I am not of either.

We are growing in number. We are manuscripts.

We do not burn.

Log in or register to write something here or to contact authors.