Nanoparsec (npc) is a unit of length one-billionth of a parsec, equating to about 30.857 megameters, 0.1 light-seconds, or about 4.843 Earth radii. This unit can be used to measure the sizes of planets and stars as an alternative of miles, kilometers, megameters, Earth radii, Jupiter radii, or Solar radii. For example, the mean circumference of Earth is 1.30 nanoparsecs while Jupiter's mean radius is 2.27 nanoparsecs.
| Object | Radius | Circum. |
|---|---|---|
| Ceres | 0.015 npc | 0.097 npc |
| Pluto | 0.037 npc | 0.235 npc |
| Moon | 0.056 npc | 0.354 npc |
| Kepler-37b | 0.063 npc | 0.393 npc |
| Mercury | 0.079 npc | 0.497 npc |
| Titan | 0.083 npc | 0.524 npc |
| Mars | 0.110 npc | 0.690 npc |
| Venus | 0.196 npc | 1.232 npc |
| Earth | 0.206 npc | 1.297 npc |
| Kepler-22b | 0.491 npc | 3.083 npc |
| Neptune | 0.806 npc | 5.062 npc |
| Uranus | 0.829 npc | 5.209 npc |
| Saturn | 1.877 npc | 11.791 npc |
| Jupiter | 2.267 npc | 14.242 npc |
| HD 209458 b | 3.003 npc | 18.866 npc |
| WASP-17b | 4.513 npc | 28.356 npc |
| Sun | 22.551 npc | 141.694 npc |
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