Introduction to the astronomical event
The Jeddah Astronomical Society, through its president, Engineer Majid Abu Zahra, announced a prominent astronomical event: the arrival of Jupiter, the giant of the solar system, at the end of its retrograde motion on Wednesday, March 11, 2026. After this date, the planet will reappear as if it is moving eastward in front of the constellations in the sky, after months of appearing to move westward.
What is retrograde motion? The scientific explanation
Engineer Abu Zahra explained that the phenomenon of planetary retrograde motion is actually an optical illusion, not a true reversal in the planet's orbit. This phenomenon arises due to the difference in orbital speeds of the planets around the sun. Earth, being closer to the sun, moves in its orbit at a faster speed compared to the outer planets like Jupiter. When Earth catches up with Jupiter in its orbit and overtakes it, it appears to an observer on Earth that Jupiter is moving backward, just as you feel when you overtake a slow car on the highway; the other car appears to be reversing.
Historical context: A mystery that puzzled the ancients
Historically, the retrograde motion of the planets has been a major puzzle for astronomers of antiquity. Astronomers like Ptolemy attempted to explain this phenomenon with complex models that assumed the planets revolved in small circles (epochs) within their larger orbits around the Earth. This puzzle was not scientifically solved until the advent of the heliocentric model proposed by Nicolaus Copernicus, which proved that the Earth and the planets revolve around the Sun, thus providing a logical and accurate explanation for this motion. Furthermore, observations of Jupiter have always been linked to groundbreaking discoveries, such as Galileo Galilei's discovery of Jupiter's four largest moons in 1610.
The importance of the event and its impact on astronomical observation
This phenomenon is of great importance both locally and internationally. Locally, the clear skies of Saudi Arabia offer an ideal opportunity for astronomy enthusiasts and photographers to document this event. Internationally and regionally, these phenomena represent a valuable educational opportunity for scientific institutions and schools to explain the dynamics of the solar system to the public and students, thus enhancing scientific awareness of astrophysics.
Monitoring and observation details
Abu Zahra noted that Jupiter's retrograde motion began on November 11, 2025. During this period, the planet reached opposition with the Sun on January 10, 2026, a phase when it was at its best for observation. With the retrograde motion ending today, Jupiter will resume its normal movement and gradually begin to appear closer to the Sun in the sky over the coming months, indicating that the ideal viewing period is drawing to a close.
Despite this, observing Jupiter remains possible and enjoyable this evening shortly after sunset. The planet will appear as a very bright object, easily distinguishable to the naked eye as a fixed point of light that does not flicker like a star. As darkness falls, it will rise higher in the southern sky, remaining visible for several hours before moving towards the western horizon. Binoculars or small telescopes are recommended to observe the planet's prominent details and its large moons orbiting it in a spectacular astronomical display.
