Emma is creating a model of the sun, Earth, and moon. She uses wire to keep the three objects in orbit around each other. Emma knows that Isaac Newton’s law of universal gravitation states that every object in the universe attracts every other object. This attraction keeps Earth in orbit around the sun and the moon in orbit around Earth. Different alignments of the Earth, moon, and sun can cause phenomena to occur on Earth. These phenomena are caused by differences in gravitational pulls. What are these phenomena called?