Re: When you observe the sun (each day), why does it move to the south?

Dear Amy:

The path of the Sun appears to move south from the June Solstice (about June 21) to the December Solstice (about December 21). From the December Solstice to the June Solstice the Sun's path appears to move to the north.

The axis of the Earth is not perpendicular to the orbital plane. The axis is tilted at about 23 1/2 degrees. If the axis was not tilted there would be no seasons and the lengths of day and night would always be equal.

At the December Solstice the length of day is shortest in the northern hemisphere and longest in the southern hemisphere. This is the beginning of winter in the north, and summer in the south. The Sun is at its farthest point south in its path across our sky.

After the December Solstice the Sun will move northward along its path until the June Solstice when it reaches its farthest northerly point. At the June Solstice the length of day is longest in the northern hemisphere and shortest in the southern hemisphere. This is the beginning of summer in the north, and winter in the south.

Most model globes of Earth are orientated to show the tilt of the axis. Take a look at the Earth globe at your school or at home. Notice the tilt and how the North Pole is not really at the top of the globe, and the South Pole is not quite at the bottom, and how the equator is not parallel to the floor. Your globe may have a figure-8 type graph on it in the eastern Pacific Ocean. This is called an analemma. It shows the latitudes where the Sun is directly overhead at noon throughout the year.

Best Regards,

Rick De Van

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Richard T. De Van
Salt Lake City, Utah 
rdevan@rtd1.com