The number of daylight hours on a summer day depends upon latitude and can vary from slightly more than 12 hours to a full 24 hours in the northern hemisphere. At any given latitude above the equator, the longest day falls on the summer solstice, which is usually June 21.
The Earth does not face the sun at equal amounts throughout the year because it tilts at an angle of 23.5 degrees. This results in the sun being visible longer in the Northern hemisphere when the North Pole tilts towards it. During the summer solstice, the sun reaches its highest point in the Northern hemisphere's sky and is at its lowest during the winter solstice. The farther north one travels, the longer the day gets. However, the opposite is true at the other pole. When the Arctic Circle experiences 24-hour days, the Antarctic never sees the sun.Learn More
In the United States, afternoon is generally the time between noon and 5:00 p.m., and evening is considered anything after 5:00 p.m. There is no set allocation for afternoon and evening, however. The determination of the two is largely lifestyle driven, and the concepts of the two may vary slightly around the globe but is generally regarded to correspond with the end of the workday and the time at which dinner is traditionally eaten.Full Answer >
The change in seasons is caused by the varying angle of the Earth's tilt from one part of the year to another. A common misconception is that the change in seasons is due to the Earth's slightly elliptical orbit bringing the planet closer to the sun in summer, but, as About.com notes, seasons are different in the northern hemisphere and the southern, which are the same distance from the sun.Full Answer >
B.C. and A.D. are short for "Before Christ" and "Anno Domini," respectively. The latter is a shortened form of the Medieval Latin phrase "Anno Domini Nostri Iesu Christi," which translates as "In The Year of Our Lord Jesus Christ."Full Answer >
There are 52 recognized work weeks in a year. This is based on a regular calendar year in the United States where employees work a 40-hour work week.Full Answer >