Constants

Mathematical

pi, π
τ
e
golden_ratio, φ

Named numbers

Large numbers

hundred
thousand
million
billion
trillion
quadrillion
quintillion
googol

Unicode fractions:

½, ⅓, ⅔, ¼, ¾, …

Colloquial:

quarter
half
semi
double
triple
dozen

Physics

Description	Identifier	Dimension
The speed of light in vacuum	`speed_of_light`, `c`	`Velocity`
The Newtonian constant of gravitation	`gravitational_constant`, `G`	`Force × Length^2 / Mass^2`
Standard acceleration of gravity on earth	`gravity`, `g0`	`Acceleration`
The Planck constant	`planck_constant`, `ℎ`	`Mass × Length^2 / Time`
The reduced Planck constant	`h_bar`, `ℏ`	`Mass × Length^2 / Time`
Mass of the electron	`electron_mass`	`Mass`
Elementary charge (charge of the electron)	`elementary_charge`, `electron_charge`	`ElectricCharge`
Magnetic constant (vacuum magnetic permeability)	`magnetic_constant`, `µ0`, `mu0`	`Force / Current^2`
Electric constant (vacuum electric permittivity)	`electric_constant`, `ε0`, `eps0`	`Capacitance / Length`
Bohr magneton	`bohr_magneton`, `µ_B`	`Energy / MagneticFluxDensity`
Fine structure constant	`fine_structure_constant`, `alpha`, `α`	`Scalar`
Proton mass	`proton_mass`	`Mass`
Neutron mass	`neutron_mass`	`Mass`
Avogadro constant	`avogadro_constant`, `N_A`	`1 / AmountOfSubstance`
Boltzmann constant	`boltzmann_constant`, `k_B`	`Energy / Temperature`
Stefan-Boltzmann constant	`stefan_boltzmann_constant`	`Power / (Area × Temperature^4)`
Ideal gas constant	`gas_constant`, `R`	`Energy / (AmountOfSubstance × Temperature)`
Planck length	`planck_length`	`Length`
Planck mass	`planck_mass`	`Mass`
Planck time	`planck_time`	`Time`
Planck temperature	`planck_temperature`	`Temperature`
Planck energy	`planck_energy`	`Energy`
Bohr radius	`bohr_radius`, `a0`	`Length`
Rydberg constant	`rydberg_constant`	`Wavenumber`