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.
Why are Mars' seasons more extreme than those of the earth? Mars' orbit is more eccentric than our almost circular one. Mars' weather is driven by evaporation from the polar ice in its summer. Mars' axial tilt is slightly more than our 23.5 degrees. Mars' seas dried up long ago.