Initial Physical Constants
Physical Constants in the ScientificConstants package
The CODATA 1998 Adjustment
The following table lists the commonly used fundamental physical constants in the ScientificConstants package:
Atomic and Nuclear
Many of the above physical constants are derived constants. To see the definition of a constant, use the ScientificConstants[GetConstant] command. For an explanation of the derivations, see the following section.
The constants c (speed_of_light_in_vacuum), mu (permeability_of_vacuum), epsilon (permittivity_of_vacuum), and Z (characteristic_impedance_of_vacuum) are exact by definition (that is, they are assigned an uncertainty of zero). See the CODATA 1998 Adjustment for details.
The uncertainty assigned to G (Newtonian_constant_of_gravitation) is approximately 12 times larger than its previous value from the 1986 adjustment. This is due to the re-evaluation of previous results and some newer work. See the CODATA 1998 Adjustment for details.
The following table lists applied physical constants in the ScientificConstants package.
The constant g (standard_acceleration_of_gravity) is exact by definition (that is, it is assigned an uncertainty of zero). See the CODATA 1998 Adjustment for details.
The following table lists less commonly used fundamental physical constants in the ScientificConstants package.
The constant M[u] (molar_mass_constant) is exact by definition (that is, it is assigned an uncertainty of zero). See the CODATA 1998 Adjustment for details.
The values and uncertainties of the fundamental physical constants are determined experimentally. As expected, there is much multiplicity and interdependence of results.
Occasionally, the CODATA Task Group on Fundamental Constants reviews the available experimental results and theoretical constraints, and uses a statistical treatment to obtain a self-consistent set of values and uncertainties for the fundamental physical constants. This set is intended to represent our current knowledge of the values of the fundamental constants.
In the CODATA 1998 Adjustment, the result of a least-squares fitting algorithm is a set of 57 adjusted constants with associated uncertainties and correlations (that is, a covariance matrix). Most of the commonly used fundamental physical constants are derived from a subset of the adjusted constants and some other independent or exact constants. The values and uncertainties of the derived constants are determined by a usual calculation of error analysis, using the covariance matrix.
In ScientificConstants, the 1998 CODATA results are closely reflected by defining 16 nonderived constants with the values and uncertainties of 16 of the CODATA adjusted constants. Another two nonderived constants are defined as two physical constants that are closely related to two other CODATA adjusted constants.
The following table lists the 16 CODATA adjusted constants defined in ScientificConstants.
The following table lists the two other physical constants defined in ScientificConstants that are closely related to CODATA adjusted constants.
The above two constants are closely related to the CODATA adjusted constants additive correction to theoretical a[e] and additive correction to theoretical a[mu].
Furthermore, in the ScientificErrorAnalysis package, the correlations between pairs of the above 18 constants are defined.
Similar to the CODATA 1998 Adjustment, most of the commonly used fundamental physical constants are defined in ScientificConstants as derived constants in terms of the above 18 constants and some other independent or exact constants.
The derived constants of ScientificConstants are treated as quantities-with-error with functional dependence by the ScientificErrorAnalysis package.
For a discussion of the connections between the ScientificErrorAnalysis and ScientificConstants packages, see ScientificErrorAnalysis and ScientificConstants.
Details of Commands for Physical Constants
ScientificErrorAnalysis and ScientificConstants
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