Albert Einstein first outlined his general theory of relativity in 1915, and published it the following year. He stated it in one equation, which is actually a summary of 10 other equations. The video above explains what it all means.
The equations completely changed how we understood the nature and evolution of the Universe, says Katie Mack of the University of Melbourne in Australia."Fundamental to this new view is the idea that space-time, the basic fabric of reality, is malleable."
General relativity provided a new picture of how gravity works. Instead of massive objects exerting a pull on other objects, they distort space and time around them.
The physicist John Wheeler summed it up succinctly: "Space-time tells matter how to move; matter tells space-time how to curve."
Einstein's equation can tell us how our universe has changed over time, and offers glimpses of the earliest moments of creation. It is no surprise that it is the favourite of many scientists.
"The insight provided by this equation shapes our view of how the Universe works at its most fundamental level," says Mack.
Pedro Ferreira of the University of Oxford in the UK also has a soft spot for Einstein's 10 equations.
"Written carefully they are so compact and simple, a little squiggle on the paper," says Ferreira. "But they are a treasure trove of information."
Since Einstein first published them, the equations have been used to predict the existence of black holes and gravitational waves, and to infer that the universe is expanding. "I think that is why I consider them beautiful, because they contain so much richness and complexity in them and because they seem, so far, so incredibly true," says Ferreira.
Read more: What is the most beautiful equation?