One way to triangulate the distance to many remote objects, such as stars, is to observe the shifts in their location relative to more distant background objects. This apparent shifting of an object$$s location with respect to the background objects is known as parallax. Parallax is represented in the figure, where the top image shows the parallax shift that is observed along a baseline that runs from one side of Earth to the other. The bottom two images show what the observer sees from opposite sides of Earth. Using triangulation, the distance to the object can be calculated with simple trigonometric relations.