Rocky planet & Moon size comparisons
Leave familiar metres behind. Compare the diameters of rocky worlds and our Moon.
Finding a little perspective…
Inside The rocky neighborhood
Use the same NASA diameter table for terrestrial planets, the Moon and Pluto.
Use Earth as a familiar starting point
Earth, Venus, Mars and Mercury share this collection with our Moon and Pluto. Focus on the solid world inside each outline. The Moon and dwarf planet broaden the comparison beyond planets without changing the task: estimate a diameter on the same scale as the reference.
Diameter does not show orbital distance
These rounds use NASA reference diameters, with an equatorial convention for planets. The spacing on screen is chosen for play, not to show where the worlds orbit. A diameter comparison also does not tell you the relative mass or volume; those require different measurements or calculations.
Learn the references, then try again
Every reveal explains the measurement and links to its source. These five pairs keep the same order when you replay, with a separate best score for this collection saved in your browser.