# The Solar System at a glance: eight planets, measured

Eight planets, one spreadsheet. Mean radii, day and year lengths, and moon counts - with live formulas computing how many Earths fit inside each planet.

Values are from NASA's Planetary Fact Sheet (mean radius, sidereal/orbital periods). Moon counts are the confirmed tallies as of 2024; they keep climbing as surveys find more, so treat that column as a snapshot.

@sheet Planets
@style A1:G1: bold
| Planet | Radius (km) | Volume (Earth = 1) | Moons (2024) | Distance from Sun (AU) | Year (Earth days) | Day length (hours) |
| --- | --- | --- | --- | --- | --- | --- |
| Mercury | 2440 | =(B2/$B$4)^3 | 0 | 0.39 | 88.0 | 4222.6 |
| Venus | 6052 | =(B3/$B$4)^3 | 0 | 0.72 | 224.7 | 2802.0 |
| Earth | 6371 | =(B4/$B$4)^3 | 1 | 1.00 | 365.3 | 24.0 |
| Mars | 3390 | =(B5/$B$4)^3 | 2 | 1.52 | 687.0 | 24.7 |
| Jupiter | 69911 | =(B6/$B$4)^3 | 95 | 5.20 | 4333 | 9.9 |
| Saturn | 58232 | =(B7/$B$4)^3 | 146 | 9.58 | 10759 | 10.7 |
| Uranus | 25362 | =(B8/$B$4)^3 | 28 | 19.2 | 30687 | 17.2 |
| Neptune | 24622 | =(B9/$B$4)^3 | 16 | 30.1 | 60190 | 16.1 |
@endsheet

## Things worth noticing

- Jupiter's volume works out to about 1,321 Earths. Every other planet combined fits inside it with room to spare.
- Venus rotates backwards and so slowly that its day (measured by the Sun) outlasts its year.
- Saturn's moon count overtook Jupiter's in 2023 when 62 new moons were confirmed in one announcement.
- Mercury's "day" column is its solar day: because it rotates three times for every two orbits, one sunrise-to-sunrise cycle lasts 176 Earth days, twice its year.

## Formulas at work

The Volume column is a live formula: `=(B2/$B$4)^3` cubes the ratio of each planet's mean radius to Earth's. Change a radius and every volume recalculates. That's the point of a living document - correct the numbers as measurements improve and the comparisons take care of themselves.

Sources: NASA Planetary Fact Sheet (nssdc.gsfc.nasa.gov/planetary/factsheet), IAU moon designations. License: CC-BY-4.0 - reuse freely with credit.