Muslims pray in direction of the Kaaba located in Mecca, Saudi Arabia. This direction is called the Qiblah. Next Friday the 27th of May 2016, the sun will be right above the Kaaba.

Everyone knows that, for each ritual celebration, Muslims around the world turn towards the direction of the Kaaba. Twice a year – in May and July, an exceptional celestial event occurs: the sun is approaching the zenith of Mecca to find over the Kaaba.

At every moment, the Sun runs above our heads. So that it would be possible to establish a path and even a virtual route on land, as if traveling on. The Sun’s position is such as it systematically corresponds to a geographically localized place on earth.

Imagine that the Sun is a ball whose shadow is cast on the ground. Well, we could draw the path taken by the shadow and locate, depending on the time of day, some places on earth simply by looking at the Sun, provided that these places are located between the two tropics, as it is the case for Mecca. This is particularly interesting for Muslims.

This event takes place because the Sun changes its apparent position in relation to Earth’s observers throughout the seasons of a single terrestrial year. This leads the Sun to pass at the Zenith of several location on Earth twice per year; including Kaaba.

Sun is highest in the sky at noon, but this highest point (zenith) varies by latitude and by season of the year. Earth is tilted by 23.5degrees from a position perpendicular to its orbital plane. Earth’s tilt remains fixed as it orbits the sun.

As Earth orbits the sun, the north pole tilts toward the sun part of the year, and away from the sun part of the year. The sun rays shine down perpendicularly at a different latitude each day because of this tilt and its orbit around the sun.

Every year on June 21-22, the Sun’s perpendicular rays (witnessed by 90degrees position of sun at noon) shine down at 23.5degrees North latitude (Tropic of Cancer). Annually also from June to September 21, the Sun’s perpendicular rays migrate from 23.5degrees North latitude to the equator (Zero degrees latitude). Then from September to December 21, the Sun’s perpendicular rays migrate from the equator to 23.5degrees South latitude (Tropic of Capricorn). Add from December to March 21, the Sun’s perpendicular rays migrate from 23.5degrees South latitude to the equator.

If heavy clouds prevent you from seeing the Sun that day, repeat the next day or the day after. The Sun will almost be in the same position.

We need to specify one last point: no need to cry foul in your mosque under the pretext that the qibla is not to close the graph indicated by the position of the Sun. It is acceptable in Islamic Shari’ah that the qibla is somewhat shifted.

You can check this astronomical process through this interactive animated application from the University of Nebraska–Lincoln.