You may have heard the phrase "The planet Mercury is in retrograde"... but what does that actually mean? Professor Brian Cox explains all. | BBC Two

We created this animation to visualize the captivating retrograde motion of Saturn — a cosmic illusion that has puzzled skywatchers for millennia. In 2025, Saturn begins its retrograde on July 13 and continues this apparent backward journey through the stars until November 15. But what exactly is retrograde motion? It’s not that Saturn actually reverses its orbit — instead, it’s an optical illusion that occurs when Earth, on its faster inner orbit, overtakes the slower-moving Saturn. As we pass

Mercury’s retrograde motion This video explains Mercury’s apparent retrograde motion in our skies: the inner planet appears to retrace its steps a few times per year. Every planet does this, every year. Retrograde motion is an optical illusion caused by differences in the planets’ orbital speeds. When a planet seems to reverse its direction in the sky, it’s called retrograde motion (from the Latin word retrogradus – "going backward"). Courtesy: Star Walk Based on video by James O'Donoghue / NASA