constants

Collection of physical constants and conversion factors.

Physical constants

g Earth standard gravity in \(\sf ms^{-1}\)
h Planck constant in \(\sf Js\)
k Boltzmann constant in \(\sf JK^{-1}\)
c Speed of light in \(\sf ms^{-1}\)
N_A Avogadro constant in \(\sf mol^{-1}\)
K, zero_celsius Kelvin at 0 Celsius
R Universal gas constant in \(\sf J mol^{-1}K{^-1}\)
molar_mass_dry_air Molar mass for dry air in \(\sf kg\,mol^{-1}\)
molar_mass_water Molar mass for water vapor in \(\sf kg\,mol^{-1}\)
gas_constant_dry_air Gas constant for dry air in \(\sf J K^{-1} kg^{-1}\)
gas_constant_water_vapor Gas constant for water vapor in \(\sf J K^{-1} kg^{-1}\)

Mathematical constants

golden Golden ratio

SI prefixes

yotta \(10^{24}\)
zetta \(10^{21}\)
exa \(10^{18}\)
peta \(10^{15}\)
tera \(10^{12}\)
giga \(10^{9}\)
mega \(10^{6}\)
kilo \(10^{3}\)
hecto \(10^{2}\)
deka \(10^{1}\)
deci \(10^{-1}\)
centi \(10^{-2}\)
milli \(10^{-3}\)
micro \(10^{-6}\)
nano \(10^{-9}\)
pico \(10^{-12}\)
femto \(10^{-15}\)
atto \(10^{-18}\)
zepto \(10^{-21}\)

Non-SI ratios

ppm \(10^{-6}\) parts per million
ppb \(10^{-9}\) parts per billion
ppt \(10^{-12}\) parts per trillion

Binary prefixes

kibi, KiB \(2^{10}\)
mebi, MiB \(2^{20}\)
gibi \(2^{30}\)
tebi \(2^{40}\)
pebi \(2^{50}\)
exbi \(2^{60}\)
zebi \(2^{70}\)
yobi \(2^{80}\)
KB \(10^3\)
MB \(10^6\)

Earth characteristics

earth_mass Earth mass in \(\sf kg\)
earth_radius Earth radius in \(\sf m\)
atm Standard atmosphere in \(\sf Pa\)