Science quiz
Solar System Knockout: Size, Mass, Gravity and More
Each round names a measure such as density or the length of a year. Click the world with the highest figure among those still standing and it leaves the board.
- Format
- Strongest link
- Items
- 9 rounds
- Limit
- 3:00
- Level
- Medium
- Checked
- 2026.10.03
Standard: a wrong pick loses the round, the true leader still leaves and the game goes on.
- Board
- 10 world buttons
- Rounds
- 9, a measure each
- Games
- 6, dealt in turn
- Time limit
- 3:00
- A wrong pick
- Loses the round
- Each round names a measure and the date of its figures. Click the one with the highest figure among those still standing; it leaves the board.
- No round is a coin toss: the leader is always more than 5 percent clear of the runner up.
- The figures of the last round are shown under the buttons. Keys: type a name to jump to its button, Enter to pick.
- Pause whenever you like (Esc). The board hides while the clock is stopped.
Click the world with the highest figure for the round. The buttons and the first round appear when you start.
About this quiz
6 games take turns, each with ten of the thirteen worlds and nine rounds. Every figure is shown once its round is over.
- A round is only asked when the leader is more than five percent ahead of the runner up, or at least one letter ahead.
- The time for one rotation ignores direction, so backwards spinning Venus counts with its 243 days.
- The dwarf planets are Ceres, Pluto, Haumea, Makemake and Eris.
- A wrong pick still removes the true leader, so the next round is the same for everyone.
Sources
- [1]NASA Jet Propulsion Laboratory. Planetary Physical Parameters.
Note on the data. Every figure is read from the shared solar system data; masses are shown as multiples of Earth's. 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
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|---|---|---|---|---|---|
| 01 | Solar system criteria: one world fits them all Spins backwards, less dense than 2 g/cm³, one of the eight planets? Each prompt lists two or three criteria that only one world meets. Click it. Science / Pick the match / 9 to match | Science | Pick the match | 9 | 2026.10.03 |
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