Since most (but not all, e.g. fine structure constant) physical constants have dimensions and units, I think it's probably best to wait for a Boost units library before we get too serious about this.

In the mean time, maybe people could start collecting physical constants, uncertainties, units, and references (journals, technical publications, or standard texts, if possible). I'd suggest we try to stick to SI units (MKS).

NIST's Reference on Constants, Units, and Uncertainty may provides a good source of constants. For example, Universal Constants.

How should we format our collection such that it's easy to incorporate into a library once the units framework is working? Maybe try things out on these...

namespace fundamental_physical_const { c = speed_of_light_vacuum = 299792458 * m / s; // exact mu_0 = magnetic_const = pi * 4.e-7 * N / A/A; // exact epsilon_0 = electric_const = 1. / mu_0 / c/c; // exact, (F/m) Z_0 = mu_o * c; // exact, (Ohms) G = gravitational_const = 6.673e-11 * m*m*m / kg / s/s; // 1998 CODATA recommended values gravitational_const_uncertainty = 1.0e-15 * m*m*m / kg / s/s; planck_const = 6.62606876e-34 * J * s; // 1998 CODATA recommended values planck_const_uncertainty = 5.2e-41 * J * s; }

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