A vector is a mathematical construct that has magnitude and direction. The cross product of two vectors is a binary operation in three-dimensional space that results in a third vector that is ...
In the present situation, both Earth and Mars are moving in the same direction around the Sun, but the slower one, Mars, appears to move backwards compared to the faster one, Earth. Just an illusion. The retrograde motion of Mars â like the apparent motion of the slower car on the highway â is nothing more than an illusion.
It is due to this reason that a snake becomes almost immobile on the smooth surface of glass. Snakes of sandy desert would have found themselves in a sad plight for another reason. Minute grains of desert sand constantly slip underneath so it is not possible for the snake to move forward by pressing its tail in sand. On the contrary, when lunging forward it will only succeed in making a furrow in the sand.