蜜桃av

The location of the Sun in the sky at noon local time ( 12:40 pm EST/1:40 pm EDT in Collegedale, TN) varies from day to day. During the summer the noon Sun is very high, whereas in the winter it is very low. In addition to this north-south variation, there is a slight east-west variation. The result of these changes is that the Sun's location at noon makes an elongated figure eight called an analemma. 

This change in the Sun's position at noon is demonstrated by this pole and the flower at the top. In the summer when the noon Sun is high, the bright spot in the center of the flower's shadow is close to the pole. In the winter, the bright spot is far north of the pole. Over a year the noon bright spots trace the analemma on the pavement. 

Because Collegedale is located at the far western edge of the eastern time zone, local noon is at 12:40 pm, except during daylight saving time when it is at 1:40 pm. 

The cause of the variation in the Sun's noon location north-south (up-down) is the tilt of the Earth's axis compared to its plane of revolution. 

The cause of the slight east-west (left-right) variation in the Sun's noon location is because the Earth's orbit is slightly elliptical, not circular. 

This analemma was brought to life by Dr. Henry Kuhlman (School of Engineering and Physics), Randy Craven (School of Visual Art and Design), and Dr. Sean Walters (School of Engineering and Physics).