This image shows different objects that rotate. Rotational period is the time it takes for that object to rotate just once.
Rotational period is the term describing the length of time necessary for a space object to make one complete rotation. This time varies from planet to planet, and on Earth it is 1 day.
This length of time is not constant, and in fact the Earth’s rotational period is slowing (by 0.002 seconds every hundred years). This is because of the Moon’s influence on our rotation. Sometimes collisions are also thought to slow rotational periods, and this is how scientists explain Venus’ rotation. Venus has a retrograde (backwards) rotation, and it is very slow. In fact, it is so slow that it revolves around the Sun faster (by about 17 Earth days) than it spins around its own axis. This means that a Venus day is longer than a Venus year!
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