Science quiz
Solar system criteria: one world fits them all
The eight planets and the five dwarf planets are on the board. Each prompt gives two or three criteria that exactly one of them meets. Nine prompts, two tries each.
- Format
- Pick the match
- Items
- 9 to match
- Limit
- 4:00
- Level
- Hard
- Checked
- 2026.10.03
- Prompts
- 9
- Bank
- World buttons, A to Z
- Time limit
- 4:00
- A miss
- 2 tries, then the answer is shown
- Each criteria appears in turn. Click its match in the bank.
- Used answers leave the bank. Keys 1 to 9 pick the first nine buttons; type a name to jump to it.
- Skip (0) sends a prompt to the back of the queue.
- Pause whenever you like (Esc). The board hides while the clock is stopped.
Click the one world that fits every criterion. The bank appears when you start.
About this quiz
Every prompt is a small sieve over thirteen worlds. No criterion is spare: drop any one of them and a second world fits.
- Nine prompts lead to nine different worlds.
- Three of the thirteen spin backwards: Venus, Uranus and Pluto.
- Size is the mean radius, and a year is the time for one orbit of the Sun.
Sources
- [1]NASA Jet Propulsion Laboratory. Planetary Physical Parameters.
Note on the data. The prompts are dealt in code from a fixed seed over criteria computed from the shared solar system data, and the tests prove that exactly one world fits each prompt. Radii, masses, densities, rotation and orbital periods, gravity and escape velocities are the figures in the JPL Solar System Dynamics tables of planetary physical parameters, read on 3 October 2026. The five dwarf planets are the five in that table, which are the five the International Astronomical Union recognises.
Last checked October 3, 2026
More quizzes like this
| No. | Quiz | Section | Format | Items | Added |
|---|---|---|---|---|---|
| 01 | Solar System Knockout: Size, Mass, Gravity and More Ten worlds from the eight planets and five dwarf planets, nine rounds. Each round names a measure: knock out the highest world still standing. Science / Strongest link / 9 rounds | Science | Strongest link | 9 | 2026.10.03 |
| 02 | Planet, dwarf planet or moon? Triton, Makemake, Titania, Ceres: 34 worlds of the solar system, one at a time. Is it a planet, a dwarf planet or a moon? Click the right box. Science / Sort into groups / 34 to sort | Science | Sort into groups | 34 | 2026.10.03 |
| 03 | Planets in order from the Sun Put the eight planets of the solar system in order of their distance from the Sun, then see each planet's average distance revealed. Science / Put them in order / 8 to sort | Science | Put them in order | 8 | 2026.10.02 |