Venus Orbit Semi-Major Axis
| Value | 1.0821e11 m |
| Status | Conventional / typical value |
| Source | NASA NSSDC Planetary Fact Sheet, Venus (semimajor axis) |
| Categories | Astronomicalsolar-systemplanets |
| Planck length | 6.6951069e+45 lP |
| femtometer | 1.0821000e+26 fm |
| picometer | 1.0821000e+23 pm |
| bohr radius | 2.0448726e+21 a0 |
| angstrom | 1.0821000e+21 Å |
| nanometer | 1.0821000e+20 nm |
| micrometer | 1.0821000e+17 μm |
| thou | 4.2602362e+15 thou |
| point | 306,737,010,000,000 pt |
| millimeter | 108,210,000,000,000 mm |
| pica | 25,561,417,000,000 pc |
| centimeter | 10,821,000,000,000 cm |
| inch | 4,260,236,200,000 in |
| decimeter | 1,082,100,000,000 dm |
| hand | 1,065,059,100,000 hh |
| link | 537,908,610,000 li |
| foot | 355,019,690,000 ft |
| US survey foot | 355,018,980,000 ftUS |
| yard | 118,339,900,000 yd |
| meter | 108,210,000,000 m |
| fathom | 59,169,948,000 ftm |
| rod | 21,516,345,000 rd |
| chain | 5,379,086,100 ch |
| cable length | 584,287,260 cb |
| furlong | 537,908,610 fur |
| kilometer | 108,210,000 km |
| mile | 67,238,577 mi |
| nautical mile | 58,428,726 nmi |
| league | 22,412,859 lea |
| megameter | 108,210 Mm |
| Earth radius | 16,984.775 REarth |
| light-second | 360.94971 ls |
| lunar distance | 281.50437 LD |
| solar radius | 155.54118 Rsun |
| light-minute | 6.0158285 lmin |
| astronomical unit | 0.72333917 AU |
| light-year | 0.000011437806 ly |
| parsec | 0.0000035068473 pc |
| kiloparsec | 3.5068473e-09 kpc |
| megaparsec | 3.5068473e-12 Mpc |
| gigaparsec | 3.5068473e-15 Gpc |
Learning zone
Venus's orbit is the roundest in the solar system — eccentricity 0.0068, forty times more circular than Mercury's — so its semi-major axis really is its distance from the Sun, varying by barely one per cent around the year. At 0.723 au it receives 1.9 times Earth's sunlight, which is not why the surface is hot: the clouds reflect three quarters of it straight back, and Venus actually absorbs less solar energy than Earth does. The 737 K surface is entirely the greenhouse effect's work.
The distance also makes Venus our closest planetary neighbour at inferior conjunction, about 41 million km away, and sets the 584-day rhythm of its apparitions as morning and evening star. The Mayans tabulated that cycle to a day; Galileo's observation that Venus shows a full set of phases proved it circles the Sun and not the Earth.