Tukuk-OS🪐 Solar System Explorer
ℹ️ What this tool does & how it works
A select box of ten worlds and a card of honest numbers for each: diameter in kilometres and as a multiple of Earth, distance in astronomical units, year and day in Earth measures, moons as counted today, surface gravity and mean temperature. The figures are rounded values from the NASA planetary fact sheets, and each body carries the one fact that makes it worth remembering.
Why the day of Venus is written two ways
Astronomers count a sidereal day (one full spin against the stars) and a solar day (sunrise to sunrise), and near the Sun the two differ by a year's worth of orbital motion. Venus spins so slowly — 243 Earth days sidereal, and a day longer than its 225-day year — that its rotation genuinely loses the race against its orbit, which is the sort of fact a card like this exists to make one click away.