Light year
The light year (symbol ly) is an astronomical unit of length equal to the distance light travels in a vacuum in one Julian year (365.25 days), corresponding to approximately 9.46 trillion kilometres or 5.88 trillion miles. Officially recognized by the International Astronomical Union, the term was popularized in the 19th century following Friedrich Bessel's successful measurement of the distance to the star 61 Cygni in 1838.
Metric
- Kilometre (km)9.46×10¹²
- Metre (m)9.46×10¹⁵
- Decimetre (dm)9.46×10¹⁶
- Centimetre (cm)9.46×10¹⁷
- Millimetre (mm)9.46×10¹⁸
- Micrometre (µm)9.46×10²¹
- Nanometre (nm)9.46×10²⁴
- Angstrom (Å)9.46×10²⁵
Nautical
- Nautical mile5.11×10¹²
- Fathom5.17×10¹⁵
Astronomical
- Parsec (pc)0.31
- Light year1
- Astronomical unit (au)63,241.09
- Light minute525,960.23
- Light second31,557,609.92