Simplify the following text for a Grade 9 native English-speaking person.
Original: It also has one of the slowest rotation periods of the known asteroids -- most asteroids have a rotation period in the range of 2 -- 24 hours .
Simplified: It also has one of the slowest rotation periods of the known asteroids â '' most asteroids have a rotation period in the range of 2 â `` 24 hours .