Longest rotation period (day) for a Solar System planet
- Who
- Venus
- What
- 23/56/04 hour(s):minute(s):second(s)
- Where
- Unknown (Inner Solar System,)
- When
- 01 January 0001
Venus has the longest rotation period (day) of all the major planets in the Solar System. While the Earth takes 23 hrs 56 mins 04 secs to complete one rotation, Venus takes 243.16 'Earth days' to spin once through 360 degrees. Due to its being closer to the Sun, the length of Venus' year is shorter than Earth's, lasting 224.7 days, so a day on Venus is actually longer than its year.
Another Venusian curiosity is that it rotates backwards compared to all of the other major planets (apart from Uranus, which spins on its side!). Astronomers are still unsure why.