formula.expert

Constants library

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

Astronomical 3

Astronomical Unit exact

au=1.495978707×1011 m\mathrm{au} = 1.495978707 \times 10^{11}\ \text{m}

mThe Sun–Earth yardstick, fixed by the IAU in 2012 as exactly 149 597 870 700 m and no longer tied to Earth's actual orbit.

Light-Year exact

ly=9.4607304725808×1015 m\mathrm{ly} = 9.4607304725808 \times 10^{15}\ \text{m}

mDistance light travels in one Julian year of 365.25 days — exactly 9 460 730 472 580 800 m, since both c and the year are defined.

Parsec exact

pc=3.085677581491367×1016 m\mathrm{pc} = 3.085677581491367 \times 10^{16}\ \text{m}

mDistance at which one au subtends one arcsecond — 648000/π au exactly, about 3.26 light-years, the working unit of stellar astronomy.