Unit of Measure Conversions

Astronomical Distance Conversions

INPUT value:

OUTPUT values

INPUT unit:	metre	m
	kilometre	km
	mile	mi
	astronomical unit	AU
	light year	ly
	parsec	pc

Messages:

| |

Additional Units and Information

Name	Symbol	Value	Description/Notes
astronomical unit	AU		Mean distance between the centres of the Earth and Sun
digit		1/12 diameter of the sun or moon	Used to denote the extent of an eclipse
light year	ly		Distance travelled by light through a vacuum in one Julian year (365¼ days)
lunar distance	LD	3.84399 x 10⁸ metres	Mean distance between the centres of the Earth and Moon
parsec	pc		Distance at which 1 AU subtends an angle of 1 arcsecond
		1.3 parsecs	Distance to Proxima Centauri, the nearest star beyond the solar system - a red dwarf

The Solar System

* Relative to the Earth. Viewed from above the north pole, the earth rotates on its axis in an anti-clockwise direction. It also orbits the sun anti-clockwise.
Object	Mean Distance from Sun*	Diameter*	Mass*	Gravity*	Orbital Period*
Sun		109.2	333,000	27.94
Mercury	0.4	0.383	0.055	0.38	0.24
Venus	0.7	0.95	0.815	0.91	0.62
Earth	1 AU	12,742 km	5.972 x 10²⁴ kg	9.80665 m/s²	1 yr
Moon	1 LD (from Earth)	0.273	0.012	0.17	27.3 days (sidereal) 29.5 days (synodic)
Mars	1.5	0.532	0.107	0.38	1.88
Jupiter	5.2	10.97	317.83	2.53	11.86
Saturn	9	9.14	95.162	1.07	29.46
Uranus	20	3.981	14.536	0.89	84.01
Neptune	30.1	3.865	17.147	1.14	164.8
Pluto	39.5	0.187	0.002	0.06	248.1

Useful Approximations

Approximation	% Accuracy
1 AU ≈ 15 x 10¹⁰ metres, or 150 million kilometres	99.7