Slide 30 of 49

Soon after the formation of the moon, the Earth was rotating on its axis every eight hours. Such a rapid rotational period led to winds in excess of 500 mph. The moon, which was less than 10,000 miles from the Earth at the time, exerted large gravitational forces that slowed the rotation of the Earth to its current 24 hours. Likewise, the gravity of the Earth slowed the moon's rotation so that it now matches its revolution around the earth (29 days). It the moon did not exist, the Earth's rotational rate would still be too rapid, which would lead to high winds and conditions that were unsuitable for advanced life forms.