Astronomers call this “apparent retrograde motion” because it is an optical illusion. Mercury completes its orbit around the ...

What is retroshade?, Technically speaking, retroshade refers to a planet’s “retrograde shadow period,” which occurs both ...

Mercury will begin its retrograde motion starting Aug. 23, according to the Old Farmer's Almanac, and will continue through Sept. 15. Despite its apparent backward-moving appearance, it's an ...