It might seem self-evidence that the universe is three-dimensional, but a new theory is starting to gain some traction: that the universe is a two-dimensional hologram.
Known as the “holographic principle,” it suggests that the mathematical description of the universe requires that there be one fewer dimension than we thought, so really we may just be seeing two-dimensional images overlayed on a massive cosmic horizon, according to a Space Daily report.
Scientists had only studied the holographic principle in exotic spaces with negative curvature, but because such spaces are different from the space in our own universe, the principle has only been academic and not really practical for our own universe.
But new research by scientiests at TU Wien in Vienna, Austria, suggests that the holographic principle might hold true even in flat spacetime.
In essence, our universe may function like the hologram on credit cards of bank notes that trick our brains into thinking we’re seeing a 3D image when we’re just looking at a 2D surface.
Physicist Juan Maldacena was the first to propose the idea in 1997 that there is a correspondence between gravitational theories for both curved anti-de-sitter spaces and in spaces with one fewer dimension.
We describe gravitational phenomena using a theory that requires three spatial dimensions, but quantum particles are calculated using just two spatial dimensions, and then the calculations are mapped onto each other.
Our universe, in contrast to a negatively curved one, would be quite flat with a positive curvature. However, Daniel Grumiller of TU Wien said he suspected that the correspondence principle could be valid for our universe, and tested this hypothesis with gravitational theories that live in a flat space, which he spent three years doing with his team at the university.
Now they have published an article, which has been published in the journal Physical Reviews Letters, that suggests that correspondence principle can work in a flat universe.
While it doesn’t prove we are living in a hologram, it does help scientists better understand and better explain the principles that govern our universe.