During the June Solstice and adjacent months, the opposite is true - more of the Northern Hemisphere is in sunlight than is in darkness.The opposite is true for any latitude in the Northern Hemisphere, which is more in the dark than in the light, causing nights to be longer than days. Therefore, days are longer and nights are shorter. In the left globe, representing the December Solstice, any line of latitude in the Southern Hemisphere, such as the Tropic of Capricorn, is more in sunlight than in darkness. At other times of the year, Earth's axis appears tilted toward or away from the Sun, and so the circle of illumination is not symmetrical relative to lines of reference, such as the tropics.At equinox, every location on Earth has 12 hours of sunlight and darkness. It takes the same amount of time for every location to rotate in and out of sunlight. So, the pattern of light and dark is symmetrical with respect to the equator and other lines of reference. During an equinox (the large, center globe), the tilt axis is oriented neither toward nor away from the Sun.The axial tilt remains fixed in orientation as Earth orbits the Sun, but here it is portrayed from different perspectives. To help us visualize the circle of illumination, the three larger globes are depicted as if being observed by the small figure next to the corresponding small globes. These globes show the circle of illumination at three different times of year: the December Solstice, an equinox, and the June Solstice.In contrast, at the equator, there are always 12 hours of day and 12 hours of night, irrespective of the time of year. In accordance with this, nights are longer during the winter and shorter during the summer. In such regions, days are noticeably shorter during the winter than during the summer.

In most parts of the world, there are significant differences between the length of daylight from season to season. Why Does the Length of Daylight Vary Through the Year? It finishes a complete rotation in 24 hours. As this occurs, the Sun has not changed position - the Earth has simply rotated.

The circle of illumination, the boundary between day and night, moves westward across the surface as the planet rotates eastward.

is still in the last remaining hours of night. At this later time, South America and eastern North America have rotated into the sunlight (it is morning), but the western U.S.

In the right globe, the Earth has rotated an additional four hours - the globe rotates to the right when viewed in this perspective, or counterclockwise when viewed from above the North Pole.

With a rotating Earth, this view is only an instantaneous snapshot of which areas are in sunlight and which are in darkness. At the same time, eastern South America and Africa are on the side facing the Sun and so are in daylight.

In the left globe, North America and western South America are on the side of the Earth hidden from the Sun, and so it is night.

The colored areas on these globes are time zones. When viewed straight on, as in these figures, the circle of illumination appears as a line, but it has a curved shape from any other perspective. The dashed line encircling the world separates the lighted and dark halves and is called the circle of illumination.

At any moment in time, half of the Earth's surface area is sunlit, experiencing day, and half is in the darkness of night.

What accounts for these variations? Why Does the Sun Rise and Set? Over the course of several months, however, we can notice significant changes in when and where sunrise and sunset occur. Also, the Sun does not rise or set in exactly the same direction every day, although the changes from day to day are so gradual as to be unnoticeable. THE SUN RISES EACH MORNING and sets each evening, but at slightly different times from day to day.

Which direction does the sunrise