Thread: Physical Constants

1) See answer for #2

2) If all the rules and laws of the universe work the same, I would guess constants stay the way they are due to inertia. Just as an object will continue moving in one direction until acted upon by an outside force, as far as we know a constant does not change until acted upon.

3) Having only one data point for each category to study wouldn't yield much information. We would need access to many, many universes to even begin to determine even the most basic guesses about constants.

If one of the universal constants could be changed... would we even want to? Changing something could be disastrous. Think about the gravitational constant. An increase to the force of gravity would cause poorly made structures to collapse. It might kill plants and possibly some animals, and would require most of structural engineering to be relearned to deal with more downward pull. A reduction in gravity could have devastating effects on our atmosphere. If we could change a constant... should we?

2) If the higher-level workings of reality are anything like lower-level workings, I would say nothing is needed to maintain a constant. I would guess that inertia applies.

Please define:
Higher level workings of reality
Lower level workings of reality

If one of the universal constants could be changed... would we even want to?

That's besides the point. The main issue is to think about how these constants exist at all. The motive has nothing to do with altering physical characteristics of our universe, but to develop insight into what it is that allows a physical universe to exist in the first place.

I don't think it is fruitful to think of the constants as representing "rules" of the universe. Rather they are parameters in the formulae that represent the rules. The only serious proposals that I am aware of for other universes existing is the "multiverse" ontology for quantum mechanics. Essentialy a particle is represented by a wave function psi(x), with x representing a location in space. So psi(x) provides a number, which is interpreted conventionaly as the probability of the particle being measured at location x. Integrating psi(x) over spacetime yields 1 because integrating a function is just summing it it's values at all points and the particle is someplace in the universe so the probabilities add to 1. In the multiverse ontology, we instead interpret psi(x) as the percentage of universes in which the particle is at location x. The evolution of psi(x) through time is governed by the schroedinger equation: ih(d/dt)psi(x) = Hpsi(x) (to my chagrin, i did have to look that up...). You'll notice the plank constant in there on the left side (the capital H is the hamiltonian, lets not get into that). So I would think that the planck constant, at least, would be constant across all universes (assuming these other universes exist, i'm somewhat dubious).

As far as your other questions go, they are fairly deep and I can only postulate.

1) A change in the parameters of the laws of physics would change the laws of physics: they don't change. yeah yeah, that only begs the question.

2) Within our current models, they are taken as givens (that is measured and then assumed in the models) or derived from other constants. We really don't know much about them other then that inertia has nothing to do with it.

3) When we figure out how to derive one from another or from formulae, one could say that we "understand" it.

Ultimately, these are difficult. Physics takes numbers representing measurements, runs them through formulae and returns numbers representing predictions. It does not say, how or why, only what, where and when.

Originally Posted by Invader

Please define:
Higher level workings of reality
Lower level workings of reality

Lower level here means things like the constants, the four fundamental interactions, and anything else that does not have a known cause.

Higher level here means things arising from those, like the Coriolis effect.

My original post was unclear, I will edit it.