What is Einstein's theory of general relativity?

Einstein’s theory of general relativity explains how gravity works by showing that massive objects bend space and time around them.

Imagine you're on a trampoline. If you jump on it, the surface stretches and dips around you. Now imagine your friend is really heavy, they make a bigger dip. If you roll a ball near them, instead of going straight, it curves toward them. That’s like how planets move around the Sun: space and time are bent by the Sun's mass, making planets follow curved paths.

Think of space as a stretchy fabric. When something heavy, like Earth or the Sun, sits on it, it makes a dent. Other things, like moons or spaceships, roll along this dented fabric, following its curve. That’s why we feel gravity: we’re just following the bend in space-time caused by massive objects nearby.

Time isn’t just moving forward, it slows down near heavy objects. If you had a clock on Earth and one floating far away in space, the one on Earth would tick slower. It’s like walking through deep water: it takes more effort (and time) to move.