Here's why:

* Venus rotates incredibly slowly, taking about 243 Earth days to complete one rotation. This is longer than its orbital period around the Sun, which is 225 Earth days. So, a day on Venus is actually longer than its year!

* Mercury has a rotation period of 59 Earth days.

* Earth has a rotation period of 24 hours.

* Mars has a rotation period of 24.6 hours.

Let me know if you have any other questions about the planets!