Constants

Legacy Constants

Name	Symbol	Value	Uncertainty	Units	Link
Archimedes	$\pi$	3.141 592 653 …			Wikipedia
Planck	$h$	4.135 667 696	exact	(eV∙s) x10^-15	NIST
Boltzmann	$k_{\sf{B}}$	8.617 343	0.000 015	(MeV∙K^-1) x10^-11	NIST
Speed of Light	$c$	299 792 458	exact	(m∙s^-1)	NIST
Elementary Charge	$e$	1.602 176 634	exact	(C) x10^-19	NIST
Magnetic	$\mu_{\sf{o}}$	1.256 637 062 12	0.000 000 000 19	(N∙A^-2) x10⁻⁶	NIST
Electric	$\epsilon_{\sf{o}}$	8.854 187 812 8	0.000 000 001 3	(F⋅m⁻¹) x10⁻¹²	NIST
Coulomb	$k_{\sf{e}}$	8.987 551 788 7	0.000 000 001 4	(N∙m²/C²) x10⁹	Wikipedia
Avogadro	$N_{\sf{A}}$	6.022 140 857	0.000 000 074	(mol⁻¹) ×10²³	NIST
(J) ↔︎ (eV)	J/eV	1.602 176 620 8	0.000 000 009 8	(J/eV) x10^-19	NIST
Rydberg	${\mathcal{R}}_{\infty}$	13.605 693 009	0.000 000 084	(eV)/ $hc$	NIST
Sommerfeld	$\alpha$	7.297 352 5693	0.000 000 0011	x 10^-3	NIST
Bohr	$a_{\sf{o}}$	5.291 772 109 03	0.000 000 000 80	(m) x 10^-11	NIST

Icon	Reference	Symbol	Name	Article
	seeing the Sun	$\widetilde{U}^{\sf{D}}$	mean internal energy of down quarks	Internal Energy
	seeing blood	$\mu_{\sf{o}}$	vacuum magnetic permeability	Magnetic Moments
	seeing gold	$\epsilon_{\sf{o}}$	vacuum electric permittivity
	touching ice	$T_{\sf{melt} }$	melting point of ice	Temperature
	touching steam	$T_{\sf{boil} }$	boiling point of water	Temperature
	hearing a heartbeat	$\raisebox{-0.04cm}{\it{N}} ^{\hspace{-.15cm}^{\mdsmblkcircle}} \rule{0px}{6px}^{\hspace{1px} \mathbf{\Theta}}$	time units conversion factor	Counting Bundles
	tasting a lemon	$k_{\sf{sour}}$	?	?
	tasting the ocean	$k_{\sf{salty}}$	?	?
	tasting honey	$k_{\sf{chiral}}$	chiral fine-structure constant	Atomic Hydrogen
	touching the Earth	$k_{\alpha \beta}$	terrestrial metric	Metrics
	touching the Earth	$\epsilon_{t}$	direction of time	Historical Order
	touching the Earth	$h$	Planck’s constant	Planck’s Postulate

Symbol	Name	Value	Units	Article
k_C	calorimetric reference sensation	hypothetical		Specific Energy
k_T	thermometric reference sensation	hypothetical		Vis Viva
$k _{\sf{F}}$	background pressure		(MeV∙m^-1)	Quark Models
k_τ	mean life of hydrogen	2.60534685 x 10⁵⁶	(s)	Lifetime