Quick and rough estimates for every planet’s orbit

Here are four simple rules-of-thumb to quickly calculate the average distances of each of the nine* planets from the sun.

1. The orbits of Mercury and Pluto are in a 1 : 100 ratio.
2. The orbits of Venus and Earth are in a 3 : 4 ratio.
3. The orbits of Earth, Mars, and Jupiter are in a 3 : 5 : 15 ratio.
4. Jupiter onwards, the distances are in a 1 : 2 : 4 : 6 : 8 ratio.

Sunlight reaches the earth in 500 seconds and light travels at 0.3 million km/s. The earth is therefore 150 million km from the sun.

Using these rules and the rough sun-earth distance above, the distances would be –

60, 110, 150, 250, 750, 1500, 3000, 4500, 6000 million km.

The actual distances are –

67.6, 108.2, 149.6, 227.9, 778.3, 1429.4, 2870.9, 4504.0, 5913.5 million km.

Should you base a space programme off these numbers? Probably not, but they’re very useful for quick, rough calculations. The worst (Mars) is off by nearly 10%, but the rest are all within 5% of their true value.

*I was born in the Shöwa era.

Orbits almost to scale.