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 |
span | 654,408,883,202.1 span | 1,308,817,766,404.2 span | 1,963,226,649,606.3 span | 2,617,635,532,808.4 span | 3,272,044,416,010.5 span | 3,926,453,299,212.6 span | 4,580,862,182,414.7 span | 5,235,271,065,616.8 span | 5,889,679,948,818.9 span | 6 544 088 832 021 span | 7,198,497,715,223.1 span | 7,852,906,598,425.2 span | 8,507,315,481,627.3 span | 9,161,724,364,829.4 span | 9,816,133,248,031.5 span | 10 470 542 131 234 span | 11 124 951 014 436 span | 11 779 359 897 638 span | 12 433 768 780 840 span | 13 088 177 664 042 span | 13 742 586 547 244 span | 14 396 995 430 446 span | 15 051 404 313 648 span | 15 705 813 196 850 span | 16 360 222 080 052 span | 17 014 630 963 255 span | 17 669 039 846 457 span | 18 323 448 729 659 span | 18 977 857 612 861 span | 19 632 266 496 063 span | 20 286 675 379 265 span | 20 941 084 262 467 span | 21 595 493 145 669 span | 22 249 902 028 871 span | 22 904 310 912 073 span | 23 558 719 795 276 span | 24 213 128 678 478 span | 24 867 537 561 680 span | 25 521 946 444 882 span | 26 176 355 328 084 span | 26 830 764 211 286 span | 27 485 173 094 488 span | 28 139 581 977 690 span | 28 793 990 860 892 span | 29 448 399 744 094 span | 30 102 808 627 297 span | 30 757 217 510 499 span | 31 411 626 393 701 span | 32 066 035 276 903 span | 32 720 444 160 105 span | 33 374 853 043 307 span | 34 029 261 926 509 span | 34 683 670 809 711 span | 35 338 079 692 913 span | 35 992 488 576 115 span | 36 646 897 459 318 span | 37 301 306 342 520 span | 37 955 715 225 722 span | 38 610 124 108 924 span | 39 264 532 992 126 span | 39 918 941 875 328 span | 40 573 350 758 530 span | 41 227 759 641 732 span | 41 882 168 524 934 span | 42 536 577 408 136 span | 43 190 986 291 339 span | 43 845 395 174 541 span | 44 499 804 057 743 span | 45 154 212 940 945 span | 45 808 621 824 147 span | 46 463 030 707 349 span | 47 117 439 590 551 span | 47 771 848 473 753 span | 48 426 257 356 955 span | 49 080 666 240 157 span | 49 735 075 123 360 span | 50 389 484 006 562 span | 51 043 892 889 764 span | 51 698 301 772 966 span | 52 352 710 656 168 span | 53 007 119 539 370 span | 53 661 528 422 572 span | 54 315 937 305 774 span | 54 970 346 188 976 span | 55 624 755 072 178 span | 56 279 163 955 381 span | 56 933 572 838 583 span | 57 587 981 721 785 span | 58 242 390 604 987 span | 58 896 799 488 189 span | 59 551 208 371 391 span | 60 205 617 254 593 span | 60 860 026 137 795 span | 61 514 435 020 997 span | 62 168 843 904 199 span | 62 823 252 787 402 span | 63 477 661 670 604 span | 64 132 070 553 806 span | 64 786 479 437 008 span | 65 440 888 320 210 span |
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 | spans | astronomical units | spans |
---|---|---|---|
1 | = 654408883202.1 | 4 | = 2617635532808.4 |
1.5 | = 981613324803.15 | 4.5 | = 2944839974409.4 |
2 | = 1308817766404.2 | 5 | = 3272044416010.5 |
2.5 | = 1636022208005.2 | 5.5 | = 3599248857611.5 |
3 | = 1963226649606.3 | 6 | = 3926453299212.6 |
A span is the distance measured by a human hand, from the tip of the thumb to the tip of the little finger. In ancient times, a span was considered to be half a cubit. Sometimes the distinction is made between the great span (thumb to little finger) and little span (index finger to little finger).
Name of unit | Symbol | Definition | Relation to SI units | Unit System |
---|---|---|---|---|
span | span | ≡ 9 in | = 0.2286 m | Imperial/US |
spans | astronomical units | spans | astronomical units |
---|---|---|---|
1 | = 1.5280966161506E-12 | 4 | = 6.1123864646023E-12 |
1.5 | = 2.2921449242258E-12 | 4.5 | = 6.8764347726775E-12 |
2 | = 3.0561932323011E-12 | 5 | = 7.6404830807528E-12 |
2.5 | = 3.8202415403764E-12 | 5.5 | = 8.4045313888281E-12 |
3 | = 4.5842898484517E-12 | 6 | = 9.1685796969034E-12 |
astronomical units | spans |
---|---|
1 | = 654,408,883,202.1 |
1.5280966161506 × 10-12 | = 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 …) |