astronomical unit | 1 AU | 2 AU | 3 AU | 4 AU | 5 AU | 6 AU | 7 AU | 8 AU | 9 AU | 10 AU | 11 AU | 12 AU | 13 AU | 14 AU | 15 AU | 16 AU | 17 AU | 18 AU | 19 AU | 20 AU | 21 AU | 22 AU | 23 AU | 24 AU | 25 AU | 26 AU | 27 AU | 28 AU | 29 AU | 30 AU | 31 AU | 32 AU | 33 AU | 34 AU | 35 AU | 36 AU | 37 AU | 38 AU | 39 AU | 40 AU | 41 AU | 42 AU | 43 AU | 44 AU | 45 AU | 46 AU | 47 AU | 48 AU | 49 AU | 50 AU | 51 AU | 52 AU | 53 AU | 54 AU | 55 AU | 56 AU | 57 AU | 58 AU | 59 AU | 60 AU | 61 AU | 62 AU | 63 AU | 64 AU | 65 AU | 66 AU | 67 AU | 68 AU | 69 AU | 70 AU | 71 AU | 72 AU | 73 AU | 74 AU | 75 AU | 76 AU | 77 AU | 78 AU | 79 AU | 80 AU | 81 AU | 82 AU | 83 AU | 84 AU | 85 AU | 86 AU | 87 AU | 88 AU | 89 AU | 90 AU | 91 AU | 92 AU | 93 AU | 94 AU | 95 AU | 96 AU | 97 AU | 98 AU | 99 AU | 100 AU |
light-year | 1.5812845149626 × 10-5 ly | 3.1625690299253 × 10-5 ly | 4.7438535448879 × 10-5 ly | 6.3251380598506 × 10-5 ly | 7.9064225748132 × 10-5 ly | 9.4877070897758 × 10-5 ly | 0.0001107 ly | 0.0001265 ly | 0.0001423 ly | 0.0001581 ly | 0.0001739 ly | 0.0001898 ly | 0.0002056 ly | 0.0002214 ly | 0.0002372 ly | 0.0002530 ly | 0.0002688 ly | 0.0002846 ly | 0.0003004 ly | 0.0003163 ly | 0.0003321 ly | 0.0003479 ly | 0.0003637 ly | 0.0003795 ly | 0.0003953 ly | 0.0004111 ly | 0.0004269 ly | 0.0004428 ly | 0.0004586 ly | 0.0004744 ly | 0.0004902 ly | 0.0005060 ly | 0.0005218 ly | 0.0005376 ly | 0.0005534 ly | 0.0005693 ly | 0.0005851 ly | 0.0006009 ly | 0.0006167 ly | 0.0006325 ly | 0.0006483 ly | 0.0006641 ly | 0.0006800 ly | 0.0006958 ly | 0.0007116 ly | 0.0007274 ly | 0.0007432 ly | 0.0007590 ly | 0.0007748 ly | 0.0007906 ly | 0.0008065 ly | 0.0008223 ly | 0.0008381 ly | 0.0008539 ly | 0.0008697 ly | 0.0008855 ly | 0.0009013 ly | 0.0009171 ly | 0.0009330 ly | 0.0009488 ly | 0.0009646 ly | 0.0009804 ly | 0.0009962 ly | 0.0010120 ly | 0.0010278 ly | 0.0010436 ly | 0.0010595 ly | 0.0010753 ly | 0.0010911 ly | 0.0011069 ly | 0.0011227 ly | 0.0011385 ly | 0.0011543 ly | 0.0011702 ly | 0.0011860 ly | 0.0012018 ly | 0.0012176 ly | 0.0012334 ly | 0.0012492 ly | 0.0012650 ly | 0.0012808 ly | 0.0012967 ly | 0.0013125 ly | 0.0013283 ly | 0.0013441 ly | 0.0013599 ly | 0.0013757 ly | 0.0013915 ly | 0.0014073 ly | 0.0014232 ly | 0.0014390 ly | 0.0014548 ly | 0.0014706 ly | 0.0014864 ly | 0.0015022 ly | 0.0015180 ly | 0.0015338 ly | 0.0015497 ly | 0.0015655 ly | 0.0015813 ly |
The astronomical unit (symbol: au or ua) is a unit of length, roughly the distance from Earth to the Sun. However, that distance varies as Earth orbits the Sun, from a maximum (aphelion) to a minimum (perihelion) and back again once a year. Originally conceived as the average of Earth's aphelion and perihelion, it is now defined as exactly 149 597 870 700 metres (about 150 million kilometres, or 93 million miles). The astronomical unit is used primarily as a convenient yardstick for measuring distances within the Solar System or around other stars. However, it is also a fundamental component in the definition of another unit of astronomical length, the parsec.
Name of unit | Symbol | Definition | Relation to SI units | Unit System |
---|---|---|---|---|
astronomical unit | AU | ≡ 149 597 870 700 m ≈ Distance from Earth to Sun | ≡ 149 597 870 700 m | Science - Astronomy (Length) |
astronomical units | light-years | astronomical units | light-years |
---|---|---|---|
1 | = 1.5812845149626E-5 | 4 | = 6.3251380598506E-5 |
1.5 | = 2.371926772444E-5 | 4.5 | = 7.1157803173319E-5 |
2 | = 3.1625690299253E-5 | 5 | = 7.9064225748132E-5 |
2.5 | = 3.9532112874066E-5 | 5.5 | = 8.6970648322945E-5 |
3 | = 4.7438535448879E-5 | 6 | = 9.4877070897758E-5 |
The light-year is a unit of length used to express astronomical distances. It is about 9.5 quadrillion metres or 5.9 trillion miles. As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in vacuum in one Julian year (365.25 days). Because it includes the word "year", the term light-year is sometimes misinterpreted as a unit of time.
Name of unit | Symbol | Definition | Relation to SI units | Unit System |
---|---|---|---|---|
light-year | ly | ≡ Distance light travels in vacuum in 365.25 days | = 9.4607304725808×1015 m | Science - Astronomy (Length) |
light-years | astronomical units | light-years | astronomical units |
---|---|---|---|
1 | = 63239.726345112 | 4 | = 252958.90538045 |
1.5 | = 94859.589517668 | 4.5 | = 284578.768553 |
2 | = 126479.45269022 | 5 | = 316198.63172556 |
2.5 | = 158099.31586278 | 5.5 | = 347818.49489811 |
3 | = 189719.17903534 | 6 | = 379438.35807067 |
astronomical units | light-years |
---|---|
1 | = 1.5812845149626 × 10-5 |
63,239.7263451 | = 1 |
Symbol | Definition |
---|---|
≡ | exactly equal |
≈ | approximately equal to |
= | equal to |
digits | indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …) |