Astronomical unit

Credit to Huritisho

The astronomical unit (au or AU) is a unit of distance used in astronomy to measure the distances in space. It is equivalent to the median distance between the Earth and the Sun, approximately 149 597 870.7 kilometers.

Examples of usage

References can be found on each individual object's own page.

Object	Diameter in astronomical units	Comments and reference points
Earth's circumference	0.0003	The circumference of Earth at the equator.
Light second	0.002	The distance light travels in one second is 299,792 km.
Lunar distance	0.0026	The Moon is 384,000 kilometers away from Earth at median.
Solar radius (Half of the Sun's diameter)	0.005	The radius of the Sun is 696,392 kilometers.
Light minute	0.12	The distance light travels in one minute is 17,987,520 kilometers.
Mercury	0.39	Median distance from the Sun
Venus	0.72
Earth	1.00
Mars	1.52
Ceres	2.77	The only dwarf planet in the asteroid belt.
Jupiter	5.20	Median distance from the Sun
Light hour	7.2	The distance light travels in one hour is approximately 1,079,251,200 kilometers.
Betelgeuse	8.8	Ninth brightest star in the night sky. Diameter is 950 times greater than the Sun's.
Saturn	9.58	Median distance from the Sun
VV Cephei A	17.7	One of the largest known stars
Uranus	19.23	Median distance from the Sun
VY Canis Majoris	20.5	The largest known star
Kuiper belt	30	The boundaries of the Kuiper belt begins at roughly that distance from the Sun.
Neptune	30.10	Median distance from the Sun
New Horizons	38.10	The spacecraft's current distance from the Sun.
Pluto	39.3	Median distance from the Sun
Scattered disc	45	It roughly begins at that distance from the Sun.
Kuiper belt	50	ends at that distance from the Sun
Eris	67.8	Median distance from the Sun
90377 Sedna	76	Distance at the perigee.
Light day	173	The distance light travels in one day is 2 590 000 000 kilometers.
Light year	63241	The distance light travels in approximately one Julian year is 9.47 trillion kilometers.
Proxima Centauri	268000	Closest star to the Sun.