Science quiz
Planets in order of size
Eight planets, largest to smallest. Sort them by size, then check each planet's mean radius.
- Format
- Put them in order
- Items
- 8 to sort
- Limit
- None
- Level
- Easy
- Checked
- 2026.10.03
See every entry and put the whole list in order.
- Entries
- 8
- Sort by
- Mean radius
- Time limit
- None
- Touch screens start in Tap mode: tap the entries in order, and tap one again to take it back.
- Drag mode: drag an entry (press and hold on a phone), or use the arrow buttons.
- Keyboard: space to pick up, arrows to move, space to drop.
- Pause whenever you like (Esc). The board hides while the clock is stopped.
About this quiz
The four giant planets are far larger than the four rocky ones. Jupiter's radius is about eleven times Earth's, while Mercury's is well under half.
- Uranus is slightly larger than Neptune, although Neptune has more mass.
- Venus is almost Earth's twin in size, with a radius only about 320 km smaller.
- Mars has roughly half the radius of Earth.
Sources
- [1]NASA Jet Propulsion Laboratory. Planetary Physical Parameters.
Note on the data. Mean radii and masses are taken from the JPL Solar System Dynamics table of planetary physical parameters, checked on 3 October 2026, and rounded to the nearest kilometre for display.
Last checked October 3, 2026
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