We live in a 3D world. This means we have three dimensions: height, width, and depth. But what if we can access the fourth and fifth dimensions? If we lived in a 1D or 2D world, we would see everything much differently. Think cinema, for instance, when a movie is in 3D, it means you can perceive the depth when something on the screen suddenly jumps towards your face – until that moment, you are seeing in 2D. According to theories, if we reach the other dimensions, we might break space time continuum, as we access something that humans didn’t think was possible: time. Let’s break this down.
How many dimensions are there?
We are currently living in the third dimension, where everything has a height, a width, and a depth. If we were able to go to the fourth dimension, we would access time. This concept is at the center of Einstein’s theory of relativity, where space and time are one feature, and now two separate forces.
The fourth dimension is also used to describe why humans might never be able to search the cosmos, as time is a variable we can’t control. If NASA were able to send a spaceship with astronauts four million light years away from here, considering they have access to the speed of light, they would get there almost in the blink of an eye from their perspective. On the other hand, for us on Earth, it would take millions of years, and when the astronauts’ comeback to the planet, everything they once knew and loved would not exist anymore, because time is relative.
If we lived in the fifth dimension, we would be able to do unimaginable things
Now, what would happen if we accessed the fifth dimension? In physics, this would mean we are at a place beyond space and time, an interdimensional reality outside the spacetime continuum. The first concept of the fifth dimension came from two physicists in the 1920s, Oskar Klein and Theodor Kaluza.
Kaluza and Klein were fascinated by Einstein’s idea that gravity wasn’t a force, but the result of mass bending space and time. They believed that if gravity could be explained through the curvature of space-time, then electromagnetism could also come from a hidden dimension.
According to their theory, this fifth dimension would be rolled up so tightly that we wouldn’t be able to see it. An electron, for example, would move through this hidden space, spinning around it like a hamster in a wheel. We wouldn’t notice it, but its motion would give rise to the electromagnetic force.
Because electromagnetism is much stronger than gravity, this extra dimension would need to be curled up even smaller than an atom. Scientists later discovered two more fundamental forces inside the atom — the strong and weak nuclear forces — and Kaluza and Klein’s model couldn’t account for them. Still, their work laid the foundation for what came next. Years later, a new theory brought back the idea of extra dimensions. It became known as string theory. This theory suggests that everything in the universe is made of tiny vibrating strings of energy.
String theory paired with the 5th dimension
To explain all four known forces, these strings would need to vibrate in ten dimensions. Four of them — the ones we know — are space and time. The other six are believed to be tightly curled up, far smaller than anything we can observe. The fifth dimension was already shown in movies, as the main character from the movie Interstellar, released in 2014, named Cooper, accesses this realm beyond spacetime to try to save humanity. Eleven years later, still considered by scientists the most accurate representation of the theory.