The ( apparent path ) or motion of the planets against the background of the stars , as seen from the earth , is shown in the figure above . It is evident that the path is Vakra ( curvilinear or more appropriately zig zag ) . To adequately describe the motion on a surface one has to have Direct , Retrograde, and Lateral motions . The selection of the word Vakra Gati is more appropriate than merely Direct, and Retrograde Motions . If a particle describes only the Direct and Retrograde motions then it will merely retrace its original path - which is not the case here .