Amazingly, a single day on Venus is longer than its entire year. It takes Venus 243 Earth days to completely rotate on its axis, but just 225 days to orbit the sun. Stranger still, Venus is one of two planets that rotates in reverse, a phenomenon called retrograde motion. Most theories attribute the reverse rotation to an ancient planetary collision.
astronomyblog: Retrograde motion of Mars in the... -
Copernicus' explanation for the retrograde motion of Mars (it appears to make a loop in the sky) is that we are both orbiting the Sun. If you draw Earth and Mars circling the sun and Earth overtaking Mars on the inside it looks as if Mars' motion has reversed.
What is retrograde motion? | EarthSky 2/6/17 Retrograde motion of Jupiter or Mars or Saturn in our sky is an illusion, caused by Earth’s passing these slower-moving outer worlds. But there’s a real retrograde motion, too. Animation of Mars in retrograde
Saturn Is Going Retrograde – Time To Ride The Karmic Roller Coaster!
Saturn Retrograde 2017 starts on April 6 at 27° Sagittarius and stations direct on August 25 at 21° Sagittarius. Saturn is the Lord of Karma. Retrograde motion is a time when karma is sorted out. Therefore, Saturn