1 The English language is constantly adding words to its repertoire. 2  Each year you may see a few creep into the vernacular that don't appear in the dictionary. 3  They could appeaâ¦. 4  Helping a Young Girl Understand Her First Menstrual Period Most girls experience their first menstrual period between the ages of 12 and 13.
It is also the length of a sidereal day -- the time it takes the earth to rotate 360Â°. A sidereal day could be measured using fixed stars. In conclusion the actual period of rotation of the earth is 23 hours 56 minutes and 4 seconds or 86,164 seconds.
Earth's Day and Night. Another effect of Earth's rotation is that we have a cycle of daylight and darkness approximately every 24 hours. This is called a day. As Earth rotates, the side of Earth facing the Sun experiences daylight, and the opposite side (facing away from the Sun) experiences darkness or night time.