Of course, Mercury is not going backwards, it follows its elliptical orbit around the sun as usual, all the time. It only appears to go backwards because of the relative positioning of the earth, Mercury, the sun and the apparent immobility of the stars in the sky. It is the embodiment of the phrase, 'more apparent than real'.
Of course, Mercury is not going backwards, it follows its elliptical orbit around the sun as usual, all the time. It only appears to go backwards because of the relative positioning of the earth, Mercury, the sun and the apparent immobility of the stars in the sky. It is the embodiment of the phrase, 'more apparent than real'.
It is called "apparent" motion for this reason. It was always called that - but since the '80s its been abbreviated to retrograde - which has proven more confusing. Most folks don't recognize Mercury's apparent retrogressive motion any more. I have a deep love of celestial mechanics and miss some of those more cogent terms but needs must, eh?\
Also the missive is written as entertainment as well as informative so I keep to the current standards for me readers.