General Relativistic Universe

Several Concepts of general relativity are illustrated in the card. Red and green apples represents the concept of local flatness in general relativity. The design of Buckets means the famous thought experiment by Newton, and reconsidered by Mach several hundred years later, arguing whether rotational motions are absolute or not. The design of light cones means that the speed of matters never exceeds that of light. The geodesic equations are also illustrated.