When you think of a day, you normally think of one cycle through one day and one night. That is called a solar day. Another way to measure a day is to count the amount of time it takes for a planet to completely spin around and make one full rotation. This is called a sidereal day. On Earth, a sidereal day is almost exactly 23 hours and 56 minutes.

We know how long an Earth day is, but how about the other planets in our solar system? How long does it take for those planets to spin one full rotation? And what is the best way to show the answer to this question?

The simple answer is:

Mercury: 58d 16h, 10.83 km/h

Venus: 243d 26m, 6.52 km/h

Earth: 23h 56m, 1574 km/h

Mars: 24h 36m, 866 km/h

Jupiter: 9h 55m, 45,583 km/h

Saturn: 10h 33m, 36,840 km/h

Uranus: 17h 14m, 14,794 km/h

Neptune: 16h, 9,719 km/h

In this dataset, it's possible to see all 8 planets on the sphere rotating at once and we have set Earth's ~24 hour day/rotation to happen in 60 seconds. Next to each planet's name, we have listed the time it takes for each planet to make one full rotation as well as the speed each planet moves at its equator. Jupiter, for example, makes one rotation in 9h 55m but moves 27 times faster than Earth at its equator, spinning at a whopping 45,583 km/h!

We have included two PIPs (picture in pictures) that can be toggled on for further explanation related to this concept. A PIP of the approximate sizes of the planets relative to each other and a PIP illustrating that if you viewed all the planets from the same point and at an angular diameter of 30 degrees - about ten feet from the sphere - each planet would appear to have a similar size.

Inspiration to add this dataset to our catalog came from a video that we ran across by Dr James O'Donoghue.