Comment by schmittz
14 years ago
It's often poorly explained, I completely agree, but people forget that even Planck introduced his constant just because it made the data fit. It turned out to be arguably the most fundamentally important constant (along with its reduced form) in all of physics.
Aren't all fundamental physical constants like that - they are essentially meaningless values plugged into theories to make them align with observations?
Mostly because we (humans) made up physical units (i.e. meters) while we were inventing physics. There's nothing keeping you from re-deriving physics equations without the messy constants.
http://en.wikipedia.org/wiki/Natural_units
Even then there are some dimensionless numbers that you can't get rid of (the ratio between the strength of the gravitational and coulomb forces being one obvious example).
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Natural units are nice, but they are completely impractical for dealing with normal Mirkowskian space. I.e., how do I explain to someone who cannot view me how tall I am? Our normal unit system is nice because it's phenomenological, and maybe inconvenient.
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yeahbut, some are interrelated. Like the speed of light and the permittivity of freespace (1/c^2 * mu). If you measure that constant and solve back for c, then you better get ~3 * 10^8 m/s.
That's what they look like at present, but it's possible that future theories will allow us to calculate their values from first principles.