# Scientists Just Found Proof of a Fourth Dimension

What is the fourth dimension?

It depends on who you talk to—some people think it's the dimension of time, like in *Donnie Darko*. Others think it's another dimension of space, like the designer of the game *Miegakure*.

No one's quite sure—the fourth dimension mystifies even scientists like Micho Kaku, who said he felt like *Alice in Wonderland* after reading up on it. However, two new studies published in *Nature *have started to give a better picture of the fourth dimension.

Two teams of physicists created two separate experiments that simulated what the quantum Hall effect would look like in four dimensions by using only 3-D (and some nearly 2-D) materials. Essentially, the scientists figured out how to visualize fourth-dimensional phenomena in our lower, simpler third dimension.

The applications of this are still incredibly abstract, but there may be some sci-fi levels of payoff once we wrap our heads around the fourth dimension, according to Mikael Rechtsman, one the authors of the new papers: "Maybe we can come up with new physics in the higher dimension and then design devices that take advantage the higher-dimensional physics in lower dimensions."

If you're wondering what the quantum Hall effect is, you can watch this short video explaining it:

It's understandable if all this gets a little confusing—as we mentioned, even Michio Kaku was mystified by the fourth dimension.

Even the abstract of one of the new studies is nearly impenetrable to anyone without a degree in advanced physics:

*When a two-dimensional (2D) electron gas is placed in a perpendicular magnetic field, its in-plane transverse conductance becomes quantized; this is known as the quantum Hall effect1. It arises from the non-trivial topology of the electronic band structure of the system, where an integer topological invariant (the first Chern number) leads to quantized Hall conductance.*

Sometimes it's helpful to take a step back and try to think of the fourth dimension in terms that don't involve 2-D planes of electron gas. Here's Carl Sagan describing it: