23 September 2008
Equinox at the Sphinx
Photo by Aymen Ibrahem, BA, Senior Astronomy Specialist
On 22 September, at 15:44 UTC, the Sun passed the autumnal equinox, and autumn began.
The equinox is the point of intersection between the ecliptic (Earth’s orbital plane) and the projection of Earth’s equator on the sky, termed the celestial equator.
The Sun passes the equinox twice every year, through its apparent path across the sky. On the equinox day, the Sun passes over Earth’s equator. Therefore, to an observer situated on the equator, the Sun is located on the zenith, the point on the sky directly overhead, at noon.
Intriguingly, every equinox, to an observer facing the Great Sphinx, the Sun sets beyond the right shoulder of the massive monument, or behind the southern foot of the Pyramid of King Khephren. This solar wonder is due to the precise east-west alignment of the Sphinx and the mighty Pyramids.
Aymen Mohamed Ibrahem
Senior Astronomy Specialist