We all know that the Earth takes 24 hours to complete a rotation and 365 and 1/4 days to complete a revolution. It rotates at a speed of 1000 miles per hour and revolves at a speed of 67,000 miles per hour. But, the two speeds are not the same since the evolution of the Earth. Scientists are predicting that the Earth is about 456 crores years old. It is found that 53 crores years ago it took only 21 hours to rotate and 420 days to revolve around the sun. They estimate that after 50 crores years from now it would take 27 hours to rotate and 300 days to revolve around the sun.
Do you know what is the reason behind this? The Gravitational force of the Moon! This is the reason behind the decrease in the speed of rotation of the Earth.