The Earth turns once on its axis in a little under 24 hours. Each of the other planets has its own rhythm.
The question
Which planet takes the longest to turn once on its axis?
What you do Set time running: the eight planets spin together, all at the same accelerated speed. Count each one’s turns and watch which way its white marker moves.
Without JavaScript, here are the animation’s data.
| Planet | One turn on its axis (hours) | Direction | Tilt of the axis (degrees) | Source |
|---|---|---|---|---|
| Mercury | 1,407.6 | forwards | 0.034 | 1 |
| Venus | 5,832.5 | backwards | 177.4 | 1 |
| Earth | 23.9 | forwards | 23.4 | 1 |
| Mars | 24.6 | forwards | 25.2 | 1 |
| Jupiter | 9.9 | forwards | 3.1 | 1 |
| Saturn | 10.7 | forwards | 26.7 | 1 |
| Uranus | 17.2 | backwards | 97.8 | 1 |
| Neptune | 16.1 | forwards | 28.3 | 1 |
NASA marks a backwards (retrograde) rotation with a minus sign; the table spells it out. The planets’ sizes are not to scale, and their tilts are drawn in the plane of the figure.
Mercury, the Earth, Mars and Jupiter are maps of their surface wrapped round a globe. Venus, Saturn, Uranus and Neptune are still photos: only their white marker turns.
The takeaway Venus is by far the slowest: one turn on its axis takes 243 Earth days, longer than its year. It also spins backwards, as Uranus does. The giants, by contrast, turn once in less than an Earth day.
Photo credits 8
- Global mosaic of Mercury’s surface, in black and white, made from images taken by the MESSENGER spacecraft (equirectangular projection). NASA/Johns Hopkins University Applied Physics Laboratory, Public domain, source
- Venus, wrapped in clouds, photographed by NASA’s Mariner 10 probe in February 1974. NASA/JPL-Caltech, Public domain, source
- Blue Marble: Next Generation, with land topography and sea-floor bathymetry, in equirectangular projection: map produced by Reto Stöckli, NASA Earth Observatory (NASA Goddard Space Flight Center). Reto Stöckli, NASA Earth Observatory, modified by NordNordWest, Public domain, source
- Global map of Mars, the MDIM 2.1 colour mosaic made from Viking Orbiter images (equirectangular projection). NASA / Jet Propulsion Lab / USGS, Public domain, source
- Cylindrical map of Jupiter, made from images taken by the Cassini spacecraft on 11 and 12 December 2000; its colours are close to those the human eye would see (PIA07782). NASA/JPL/Space Science Institute, Public domain, source
- Saturn in natural colour, from images taken by the Cassini probe (2008). NASA / JPL / Space Science Institute, Public domain, source
- Uranus photographed by the Voyager 2 probe in 1986. NASA/JPL-Caltech, Public domain, source
- Neptune, from the last whole-planet images taken by Voyager 2 through green and orange filters (1989); the Great Dark Spot is visible. NASA, Public domain, source
Sources 3
Williams, David R., “Planetary Fact Sheet – Metric”, NASA Goddard Space Flight Center (NSSDCA), updated 18 March 2025, rows “Rotation Period (hours)” and “Obliquity to Orbit (degrees)”, columns Mercury to Neptune (Moon and Pluto excluded).
Rotation Period (hours) 1407.6 -5832.5 23.9 655.7 24.6 9.9 10.7 -17.2 16.1 -153.3 […] Obliquity to Orbit (degrees) 0.034 177.4 23.4 6.7 25.2 3.1 26.7 97.8 28.3 119.5
Open access open the source · checked on 28 October 2026
NASA, “Venus: Facts”, section “Venus: Facts”.
your "day" would be 243 Earth days long — longer even than a Venus year (one trip around the Sun), which takes only 225 Earth days
Open access open the source · checked on 9 September 2026
Williams, David R., “Planetary Fact Sheet Notes”, NASA Goddard Space Flight Center (NSSDCA), updated 20 December 2021, definition of “Rotation Period (hours)”.
Negative numbers indicate retrograde (backwards relative to the Earth) rotation.
Open access open the source · checked on 28 October 2026