How do we detect if there is more than 1 exoplanet orbiting a star using radial velocity method? I read this but I didnt understand it. Can someone explain the answer in Laymans terms? "Multiple planets will cause a stars radial velocity curve to show two periods: a long gradual change due to the outer planet, and a shorter, sharper change due to the inner planet. The two periods are superimposed on each other, giving the radial velocity curve a complex shape".