| fermtometer | 1 fm | 2 fm | 3 fm | 4 fm | 5 fm | 6 fm | 7 fm | 8 fm | 9 fm | 10 fm | 11 fm | 12 fm | 13 fm | 14 fm | 15 fm | 16 fm | 17 fm | 18 fm | 19 fm | 20 fm | 21 fm | 22 fm | 23 fm | 24 fm | 25 fm | 26 fm | 27 fm | 28 fm | 29 fm | 30 fm | 31 fm | 32 fm | 33 fm | 34 fm | 35 fm | 36 fm | 37 fm | 38 fm | 39 fm | 40 fm | 41 fm | 42 fm | 43 fm | 44 fm | 45 fm | 46 fm | 47 fm | 48 fm | 49 fm | 50 fm | 51 fm | 52 fm | 53 fm | 54 fm | 55 fm | 56 fm | 57 fm | 58 fm | 59 fm | 60 fm | 61 fm | 62 fm | 63 fm | 64 fm | 65 fm | 66 fm | 67 fm | 68 fm | 69 fm | 70 fm | 71 fm | 72 fm | 73 fm | 74 fm | 75 fm | 76 fm | 77 fm | 78 fm | 79 fm | 80 fm | 81 fm | 82 fm | 83 fm | 84 fm | 85 fm | 86 fm | 87 fm | 88 fm | 89 fm | 90 fm | 91 fm | 92 fm | 93 fm | 94 fm | 95 fm | 96 fm | 97 fm | 98 fm | 99 fm | 100 fm |
| light-second | 3.3356409519815 × 10-24 light-second | 6.671281903963 × 10-24 light-second | 1.0006922855945 × 10-23 light-second | 1.3342563807926 × 10-23 light-second | 1.6678204759908 × 10-23 light-second | 2.0013845711889 × 10-23 light-second | 2.3349486663871 × 10-23 light-second | 2.6685127615852 × 10-23 light-second | 3.0020768567834 × 10-23 light-second | 3.3356409519815 × 10-23 light-second | 3.6692050471797 × 10-23 light-second | 4.0027691423778 × 10-23 light-second | 4.336333237576 × 10-23 light-second | 4.6698973327741 × 10-23 light-second | 5.0034614279723 × 10-23 light-second | 5.3370255231704 × 10-23 light-second | 5.6705896183686 × 10-23 light-second | 6.0041537135667 × 10-23 light-second | 6.3377178087649 × 10-23 light-second | 6.671281903963 × 10-23 light-second | 7.0048459991612 × 10-23 light-second | 7.3384100943593 × 10-23 light-second | 7.6719741895575 × 10-23 light-second | 8.0055382847556 × 10-23 light-second | 8.3391023799538 × 10-23 light-second | 8.672666475152 × 10-23 light-second | 9.0062305703501 × 10-23 light-second | 9.3397946655483 × 10-23 light-second | 9.6733587607464 × 10-23 light-second | 1.0006922855945 × 10-22 light-second | 1.0340486951143 × 10-22 light-second | 1.0674051046341 × 10-22 light-second | 1.1007615141539 × 10-22 light-second | 1.1341179236737 × 10-22 light-second | 1.1674743331935 × 10-22 light-second | 1.2008307427133 × 10-22 light-second | 1.2341871522332 × 10-22 light-second | 1.267543561753 × 10-22 light-second | 1.3008999712728 × 10-22 light-second | 1.3342563807926 × 10-22 light-second | 1.3676127903124 × 10-22 light-second | 1.4009691998322 × 10-22 light-second | 1.4343256093521 × 10-22 light-second | 1.4676820188719 × 10-22 light-second | 1.5010384283917 × 10-22 light-second | 1.5343948379115 × 10-22 light-second | 1.5677512474313 × 10-22 light-second | 1.6011076569511 × 10-22 light-second | 1.6344640664709 × 10-22 light-second | 1.6678204759908 × 10-22 light-second | 1.7011768855106 × 10-22 light-second | 1.7345332950304 × 10-22 light-second | 1.7678897045502 × 10-22 light-second | 1.80124611407 × 10-22 light-second | 1.8346025235898 × 10-22 light-second | 1.8679589331097 × 10-22 light-second | 1.9013153426295 × 10-22 light-second | 1.9346717521493 × 10-22 light-second | 1.9680281616691 × 10-22 light-second | 2.0013845711889 × 10-22 light-second | 2.0347409807087 × 10-22 light-second | 2.0680973902285 × 10-22 light-second | 2.1014537997484 × 10-22 light-second | 2.1348102092682 × 10-22 light-second | 2.168166618788 × 10-22 light-second | 2.2015230283078 × 10-22 light-second | 2.2348794378276 × 10-22 light-second | 2.2682358473474 × 10-22 light-second | 2.3015922568672 × 10-22 light-second | 2.3349486663871 × 10-22 light-second | 2.3683050759069 × 10-22 light-second | 2.4016614854267 × 10-22 light-second | 2.4350178949465 × 10-22 light-second | 2.4683743044663 × 10-22 light-second | 2.5017307139861 × 10-22 light-second | 2.535087123506 × 10-22 light-second | 2.5684435330258 × 10-22 light-second | 2.6017999425456 × 10-22 light-second | 2.6351563520654 × 10-22 light-second | 2.6685127615852 × 10-22 light-second | 2.701869171105 × 10-22 light-second | 2.7352255806248 × 10-22 light-second | 2.7685819901447 × 10-22 light-second | 2.8019383996645 × 10-22 light-second | 2.8352948091843 × 10-22 light-second | 2.8686512187041 × 10-22 light-second | 2.9020076282239 × 10-22 light-second | 2.9353640377437 × 10-22 light-second | 2.9687204472636 × 10-22 light-second | 3.0020768567834 × 10-22 light-second | 3.0354332663032 × 10-22 light-second | 3.068789675823 × 10-22 light-second | 3.1021460853428 × 10-22 light-second | 3.1355024948626 × 10-22 light-second | 3.1688589043824 × 10-22 light-second | 3.2022153139023 × 10-22 light-second | 3.2355717234221 × 10-22 light-second | 3.2689281329419 × 10-22 light-second | 3.3022845424617 × 10-22 light-second | 3.3356409519815 × 10-22 light-second |
The femtometre (American spelling femtometer, symbol fm derived from the Danish and Norwegian word femten, "fifteen"+Ancient Greek: μέτρον, metrοn, "unit of measurement") is an SI unit of length equal to 10−15 metres, which means a quadrillionth of one. This distance can also be called a fermi and was so named in honour of physicist Enrico Fermi, as it is a typical length-scale of nuclear physics.
| Name of unit | Symbol | Definition | Relation to SI units | Unit System |
|---|---|---|---|---|
| fermtometer | fm | 1000 attometres = 1 femtometre = 1 fermi = 0.001 picometre = 1×10−15 metres 1000000 femtometres = 10 ångström = 1 nanometre. | ≡ 1×10-15 m | Metric system SI |
| fermtometers | light-seconds | fermtometers | light-seconds |
|---|---|---|---|
| 1 | ≡ 3.3356409519815E-24 | 4 | ≡ 1.3342563807926E-23 |
| 1.5 | ≡ 5.0034614279723E-24 | 4.5 | ≡ 1.5010384283917E-23 |
| 2 | ≡ 6.671281903963E-24 | 5 | ≡ 1.6678204759908E-23 |
| 2.5 | ≡ 8.3391023799538E-24 | 5.5 | ≡ 1.8346025235898E-23 |
| 3 | ≡ 1.0006922855945E-23 | 6 | ≡ 2.0013845711889E-23 |
The light-second is a unit of length useful in astronomy, telecommunications and relativistic physics. It is defined as the distance that light travels in free space in onesecond, and is equal to exactly 299792458 metres (just over 186282 miles).
| Name of unit | Symbol | Definition | Relation to SI units | Unit System |
|---|---|---|---|---|
| light-second | ≡ Distance light travels in one second in vacuum | ≡ 299 792 458 m | Science - Astronomy (Length) |
| light-seconds | fermtometers | light-seconds | fermtometers |
|---|---|---|---|
| 1 | ≡ 2.99792458E+23 | 4 | ≡ 1.199169832E+24 |
| 1.5 | ≡ 4.49688687E+23 | 4.5 | ≡ 1.349066061E+24 |
| 2 | ≡ 5.99584916E+23 | 5 | ≡ 1.49896229E+24 |
| 2.5 | ≡ 7.49481145E+23 | 5.5 | ≡ 1.648858519E+24 |
| 3 | ≡ 8.99377374E+23 | 6 | ≡ 1.798754748E+24 |
| fermtometers | light-seconds |
|---|---|
| 1 | ≡ 3.3356409519815 × 10-24 |
| 2.99792458 × 1023 | ≡ 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 …) |