Constants library

4 values, each with its units, its uncertainty, and where it came from.

Universal & Atomic 2

c = 299,792,458\ \text{m/s}

m/sThe invariant speed of light in vacuum, exactly 299 792 458 m/s since 1983 — the definition that now fixes the length of the metre.

c^{2} = 8.987551787368176 \times 10^{16}\ \text{J/kg}

J/kgThe exchange rate between mass and energy in E = mc²: 8.988 × 10¹⁶ joules locked in every kilogram of rest mass.

r_{s,\odot} = 2953.25\ \text{m}

mRadius to which the Sun would have to be crushed to become a black hole, 2GM⊙/c² — a shade under three kilometres.

M_{\mathrm{Ch}} = 2.86 \times 10^{30}\ \text{kg}

kgMaximum mass a white dwarf can support by electron degeneracy pressure, about 1.44 solar masses or 2.86 × 10³⁰ kg.