Astrophysics (index)about

astronomical unit

(AU)
(about 93 million miles)

An astronomical unit (AU) is a distance unit intended to convey the distance between the Earth and the Sun, or more specifically the mean of the Earth's orbit's aphelion and perihelion. However, it is now fixed at 149597870700 meters, considered a reasonable fixed unit to approximate the Earth-Sun distance. It is commonly used for distances within the solar system and other star systems, e.g., for orbital radii. An AU is equivalent to:

Some distances in AU:

0.0026AU distance from Earth to Moon
0.0093AU diameter of the Sun
5.2AU radius of Jupiter's orbit
30AU radius of Neptune's orbit
276173AU distance to Alpha Centauri
1.6 billion AU distance to galactic center
1604 billion AU distance to Andromeda

(distance,unit,Earth,Sun,astronomy)
http://en.wikipedia.org/wiki/Astronomical_unit

Referenced by:
Achernar
astronomical quantities
Beta Centauri
Beta Pictoris b (β Pic b)
10199 Chariklo
direct imaging
Earth
evaporating gas globule (EGG)
escape velocity (Ve)
extra-solar planet
51 Eridani b
giant star
HD 80606 b
heliopause
heliosheath
heliosphere
hot Jupiter (HJ)
HR 8799
Jupiter
Kuiper Belt (K Belt)
light-year (ly)
Mars
Mercury
Neptune
Oort Cloud
parallax
parsec (pc)
Planet Nine
planetary migration
Pluto
Poynting-Robertson effect
protoplanetary disk (PPD)
radial velocity (RV)
red giant
Rigel
Saturn
Scholz's Star
Schwarzschild radius
67P/Churyumov-Gerasimenko (67P)
snow line
solar constant
Spitzer Space Telescope (SST)
supergiant
trans-Neptunian object (TNO)
Uranus
Venus
Voyager

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