🔭 Jupiter just reversed course in the sky: why?

Have you ever noticed that some planets sometimes seem to move backwards in the night sky? This puzzling phenomenon, observable with the naked eye, has intrigued observers for centuries. Jupiter, the largest planet in our Solar System, currently offers a striking illustration of this illusion.

This apparent reversal of direction, known as retrograde motion, results from an effect of perspective. Indeed, Earth moves faster in its orbit than outer planets like Jupiter. When our planet catches up to and overtakes one of them, that planet appears to temporarily move backwards relative to the fixed stars. This effect is particularly visible around opposition, the moment when the planet is opposite the Sun in our sky.


Jupiter has just finished its phase of retrograde motion, which began in November 2025. Now, since March 10, it has resumed its usual eastward course through the constellation of Gemini. Amateur astronomers can therefore easily follow it in the evening sky, where it shines with its typical brightness. This return to normal movement marks the end of a particular orbital cycle.

The planet will continue its east-west trajectory until the end of June, before temporarily disappearing from our view. It will reach solar conjunction on July 29, at which point it will be aligned with the Sun and become invisible. Jupiter will reappear in the morning sky from mid-August, offering new observation opportunities before its next retrograde episode, scheduled for December 12.


A simple amateur telescope is enough to distinguish Jupiter's cloud bands and its four main moons. Moreover, the periods around opposition are ideal, as the planet is closer to Earth and appears brighter.

These regular cycles of retrograde and prograde motion are not unique to Jupiter; all outer planets experience them. They illustrate the laws of celestial mechanics, where each orbit follows a predictable rhythm.

Planetary Opposition

Opposition occurs when an outer planet, like Jupiter or Mars, is located directly opposite the Sun relative to Earth. At that moment, the planet is visible all night, rising at sunset and setting at sunrise. This configuration optimizes observing conditions, as the planet is at its minimum distance from Earth, appearing larger and brighter.

It is also during opposition that retrograde motion is most apparent. Earth, on a smaller and faster orbit, overtakes the outer planet. From Earth's point of view, that planet then seems to stop and then move backwards in the sky before resuming its normal course. This effect lasts several weeks, its duration differing according to the observed planet.

Oppositions return at regular intervals, approximately every 13 months for Jupiter and every 26 months for Mars. They are significant events for astronomers, both amateur and professional, allowing for the study of planetary atmospheres or the photography of surface details. Astronomical calendars indicate these dates to facilitate the planning of observations.

Understanding opposition helps to grasp why planets are not always visible in the same way. This phenomenon also explains the changes in brightness and apparent size.