The universe is not just a collection of stars and planets—it is made of a four-dimensional fabric called space-time. This concept, introduced by Albert Einstein, combines the three dimensions of space with time into a single framework. Understanding this “fabric” helps explain how gravity works, how planets move, and how light travels through the cosmos.

Space-time can be imagined like a stretched rubber sheet. When a massive object, like a star or planet, is placed on the sheet, it creates a dip or curve. Smaller objects moving nearby naturally follow these curves, which is why planets orbit stars. Even light is affected, bending around massive objects in a phenomenon called gravitational lensing.

The fabric of space-time also explains why time is not the same everywhere. Clocks near massive objects run slower compared to clocks far away, a concept known as gravitational time dilation. This idea is crucial for technologies like GPS satellites, which must account for the warping of space-time to maintain accuracy.

In short, space-time is the underlying stage of the universe. It is flexible, warped by mass and energy, and connects space and time into a single, dynamic whole. Understanding this fabric is essential to grasp how the universe functions at both large and small scales.