Earth Orbit Semi-Major Axis
| Value | 1.495982612e11 m |
| Status | Conventional / typical value |
| Source | JPL Keplerian elements for the Earth–Moon barycentre, epoch J2000 |
| Categories | Astronomicalsolar-systemearth |
| femtometer | 1.4959826e+26 fm |
| picometer | 1.4959826e+23 pm |
| nanometer | 1.4959826e+20 nm |
| micrometer | 1.4959826e+17 μm |
| millimeter | 149,598,260,000,000 mm |
| centimeter | 14,959,826,000,000 cm |
| decimeter | 1,495,982,600,000 dm |
| meter | 149,598,260,000 m |
| kilometer | 149,598,260 km |
| inch | 5,889,695,300,000 in |
| foot | 490,807,940,000 ft |
| yard | 163,602,650,000 yd |
| mile | 92,956,050 mi |
| nautical mile | 80,776,599 nmi |
| astronomical unit | 1.0000026 AU |
| light-year | 0.000015812549 ly |
| parsec | 0.0000048481495 pc |
Learning zone
It is worth stating plainly that the astronomical unit and Earth's mean distance from the Sun are two different things. The au was defined in terms of Earth's orbit historically, but since 2012 it is just a fixed number of metres. Earth's semi-major axis is a measured orbital element that drifts by parts per million as Jupiter, Venus and the rest tug on us, and the value quoted here — 1.000 002 61 au for the Earth–Moon barycentre at J2000 — is a mean over those perturbations, not a permanent property.
"Mean distance" also hides an ambiguity. The semi-major axis is the average of perihelion (147.10 million km) and aphelion (152.10 million km), but the time-averaged distance is slightly larger still, because Earth spends more of the year on the slow outer part of the ellipse.