Planets Fact Table
| Body | Diameter (km) | Year length (Earth days) | Moons |
|---|---|---|---|
| Mercury | 4,879 | 88.0 | 0 |
| Venus | 12,104 | 224.7 | 0 |
| Earth | 12,756 | 365.2 | 1 |
| Moon | 3,475 | 27.3 | 0 |
| Mars | 6,792 | 687.0 | 2 |
| Jupiter | 142,984 | 4,331 | 95 |
| Saturn | 120,536 | 10,747 | 274 |
| Uranus | 51,118 | 30,589 | 28 |
| Neptune | 49,528 | 59,800 | 16 |
| Pluto | 2,376 | 90,560 | 5 |
| Body | Gravity (m/s²) | Mean temp (°C) | Day length (hours) |
|---|---|---|---|
| Mercury | 3.7 | 167 | 4,222.6 |
| Venus | 8.9 | 464 | 2,802.0 |
| Earth | 9.8 | 15 | 24.0 |
| Moon | 1.6 | -20 | 708.7 |
| Mars | 3.7 | -65 | 24.7 |
| Jupiter | 23.1 | -110 | 9.9 |
| Saturn | 9.0 | -140 | 10.7 |
| Uranus | 8.7 | -195 | -17.2 |
| Neptune | 11.0 | -200 | 16.1 |
| Pluto | 0.7 | -225 | -153.3 |
The whole solar system in two tables: all eight planets, the Moon and Pluto with their diameters, gravities, day lengths, year lengths, mean temperatures and moon counts - every figure verbatim from NASA’s NSSDC Planetary Fact Sheet, the page mission engineers quote.
The comparison tells stories the numbers alone hide: a Venusian day is longer than its year, Uranus spins on its side at -195°C, and Saturn’s moon count (274) more than doubled in 2025 alone.
How to use
- Pick a world for its fact card - the record-holders and oddities are baked into each line.
- Scan the tables for the extremes: smallest diameter (Pluto, 2,376 km), longest day (Venus, 5,832 hours), most moons (Saturn, 274).
- Cross-check gravity against the weight calculator when the numbers feel impossible.
Frequently asked questions
Why is a day on Venus longer than its year?
Venus rotates once every 5,832 Earth hours (243 Earth days) but orbits the Sun in 224.7 - and it spins backwards relative to every other planet, which is why the Sun rises in the west there. The minus sign on its rotation period in NASA’s table marks the retrograde spin.
Which planet has the most moons?
Saturn, decisively: 274 confirmed moons after the 2025 announcement of 128 new ones - more than all other planets combined. Jupiter follows with 95. The counts climb as telescopes find ever-smaller irregular moonlets.
Why is Neptune’s gravity barely higher than Earth’s?
Surface gravity depends on both mass and radius: g = GM/r². Neptune has 17 Earth masses but 3.9 Earth radii, so its surface sits far from most of that mass - 11.0 m/s². The densest punch per radius belongs to Mercury and Mars, tied at 3.7.
Is Pluto still on NASA’s planetary fact sheet?
Yes - the dwarf planet keeps its row with five moons and a -225°C mean, because the sheet catalogs bodies, not classifications. Its 2006 demotion changed the label, not the physics; its year is still 90,560 Earth days.