For centuries, people have observed the motion of planets and wondered what keeps them moving in their paths around the Sun. Isaac Newton described gravity as a force pulling objects toward one another, but Einstein’s theory of general relativity provides a deeper understanding. It shows that the motion of planets is guided not by a mysterious force but by the curvature of space-time itself.

According to general relativity, massive objects like the Sun warp the fabric of space-time around them. Planets move along the curved paths in this warped space-time, which we perceive as their orbits. In other words, planets are following the natural “rails” created by the bending of space-time. The closer a planet is to the Sun, the stronger the curvature, and the faster it moves along its orbital path.

This perspective explains several phenomena that Newtonian physics could not fully account for. For example, the orbit of Mercury shifts slightly over time in a way that puzzled scientists for decades. General relativity showed that this shift is due to the curvature of space-time caused by the Sun’s massive gravitational field.

The idea that planets follow curves in space-time also helps us understand the broader mechanics of the solar system. Each planet’s motion affects and is affected by the curvature created by other planets and stars. Even light traveling through the solar system bends slightly, following the contours of space-time.

By viewing planetary motion through the lens of space-time, we gain a more complete and accurate picture of the universe. Planets do not simply “fall” toward the Sun—they glide along invisible curves in a dynamic fabric, showing that the cosmos is not just a stage for motion, but an active participant in shaping it.