Mercury Orbit Semi-Major Axis
| Value | 5.7909e10 m |
| Status | Conventional / typical value |
| Source | NASA NSSDC Planetary Fact Sheet, Mercury (semimajor axis) |
| Categories | Astronomicalsolar-systemplanets |
| Planck length | 3.5829123e+45 lP |
| femtometer | 5.7909000e+25 fm |
| picometer | 5.7909000e+22 pm |
| bohr radius | 1.0943215e+21 a0 |
| angstrom | 5.7909000e+20 Å |
| nanometer | 5.7909000e+19 nm |
| micrometer | 5.7909000e+16 μm |
| thou | 2.2798819e+15 thou |
| point | 164,151,500,000,000 pt |
| millimeter | 57,909,000,000,000 mm |
| pica | 13,679,291,000,000 pc |
| centimeter | 5,790,900,000,000 cm |
| inch | 2,279,881,900,000 in |
| decimeter | 579,090,000,000 dm |
| hand | 569,970,470,000 hh |
| link | 287,863,870,000 li |
| foot | 189,990,160,000 ft |
| US survey foot | 189,989,780,000 ftUS |
| yard | 63,330,052,000 yd |
| meter | 57,909,000,000 m |
| fathom | 31,665,026,000 ftm |
| rod | 11,514,555,000 rd |
| chain | 2,878,638,700 ch |
| cable length | 312,683,590 cb |
| furlong | 287,863,870 fur |
| kilometer | 57,909,000 km |
| mile | 35,982,984 mi |
| nautical mile | 31,268,359 nmi |
| league | 11,994,328 lea |
| megameter | 57,909 Mm |
| Earth radius | 9,089.4679 REarth |
| light-second | 193.16363 ls |
| lunar distance | 150.64815 LD |
| solar radius | 83.238465 Rsun |
| light-minute | 3.2193939 lmin |
| astronomical unit | 0.38709776 AU |
| light-year | 0.0000061209861 ly |
| parsec | 0.0000018767029 pc |
| kiloparsec | 1.8767029e-09 kpc |
| megaparsec | 1.8767029e-12 Mpc |
| gigaparsec | 1.8767029e-15 Gpc |
Learning zone
Mercury's semi-major axis is the least representative in the solar system, because its orbit is the most eccentric of any planet: e = 0.206 carries it from 46.0 million km at perihelion out to 69.8 million km at aphelion, a 50 per cent swing in distance and a factor of 2.3 in sunlight. Combined with the 3:2 spin-orbit resonance, that eccentricity produces "hot poles" — two opposite longitudes that always face the Sun at perihelion and bake hundreds of degrees hotter than the rest of the equator.
This orbit carries more physics per kilometre than any other. Its perihelion advances 43 arcseconds per century beyond what Newtonian perturbations explain — the anomaly that led Le Verrier to invent the phantom planet Vulcan, and that general relativity resolved exactly in 1915, Einstein's first empirical triumph.