You could believe these figure-of-eight patterns are resulting from a laser show.
These weird forms represent the path of the sun, or analemma, three times a day during a year.
To make such an image, you need a pretty fancy camera called pinhole camera. This figure-of-eight path is called an analemma. It was caught in the sky over Wrocław in Poland.
As described in New Scientists:
Maciej Zapiór and colleague Łukasz Fajfrowski built a pinhole camera and set it to make 1-minute-long exposures onto a single piece of photographic paper at 1030, 1200 and 1330 each day from 1 March 2013 to 1 March 2014.
The resulting image shows how the position of the sun in the sky changes throughout the year: in the summer it is higher, in the winter lower. Its position also shifts horizontally, tracing a figure-of-eight path called an analemma.
The colour of the sun appears to change, not because of something happening in the atmosphere, but because of changes to the photographic paper due to the differing temperature and humidity throughout the year.
This animation shows a sun analemma created by the apparent motion of our star throughout one complete calendar year:
The analemma’s unique shape is the result of two unique properties of the Earth:
- The Earth’s axis of rotation is tilted 23.5º relative to the plane of the ecliptic. This tilt results in a perceived up and down (vertical) motion of the Sun when viewed from Earth.
- The shape of the Earth’s orbit is elliptical, and this causes the rate at which the Earth orbits the Sun to vary. The left and right motion (the distance from a vertical centerline) is the result of this changing rate.
- If the Earth’s orbit was perfectly circular, the analemma would become a vertical line. Further, if there were no tilt in the axis of the Earth relative to the plane of the ecliptic (and the Earth had a circular orbit), the Sun’s position would not change in this tour — it would appear in the same location each day at noon.
An amazing connection between science and art, isn’t it?