A Doughnut or a Hall of Mirrors? Experts Explores the Complex Shape of Our Universe

The universe could be more complicated than we thought, maybe looking like a giant doughnut or a hall of mirrors.

A new study in Physical Review Letters explores the intriguing idea that the universe might have a complicated structure that allows it to loop back on itself in strange ways.

Is Our Universe A Doughnut? Or A Hall of Mirrors?

Many scientists have different ideas about the shape or topology of the universe. In a world with a complicated topology, going in a straight line might lead you back to where you started, like in the old arcade game Pac-Man. As part of the COMPACT Collaboration, the researchers looked into 17 nontrivial topologies and found that many haven't been ruled out yet.

A cosmologist at the University of Michigan named Dr. Dragan Huterer talked about how interesting it would be to measure some things about the world. He expressed his excitement about the chance to take such measures.

According to him, previous studies attempted to identify similar patterns in the cosmic microwave background (CMB), a form of light that originated 380,000 years ago, during the universe's early stages. Despite all of these attempts, no proof of complex topology was found. He did say that this new study suggests that earlier searches were not thorough enough.

The 3-torus topology is one option. In this topology, the world loops around itself like a 3D Pac-Man screen. In this case, leaving one side of the cube would lead you to the other half.

No proof for such a topology has been found despite many studies.

However, some researchers, like theoretical physicist Glenn Starkman, say that the 3-torus can be shaped in many ways that haven't been fully explored yet. If the cube's sides are bent about each other, leaving the top might lead you back to the bottom, but turn around 180 degrees.

What It Means and Prospective Studies

The study results are significant because they show that the universe may have a shape that is much more complicated than was thought before. This could shed light on odd events regarding the CMB, such as unexpected large-scale patterns.

It has been noted that the universe lacks uniformity in all directions, as observed by Starkman. He described this as a highly significant and enduring enigma of the cosmos.

Despite the overall appearance of a flat world, there are various forms of flatness. When a flat piece of paper is manipulated, fascinating shapes like cylinders or Möbius strips can be created.

These shapes have the intriguing property of keeping parallel lines parallel while having distinct forms. In the same way, the world could be flat and still have a complicated, nontrivial topology.

The researchers want to use machine learning to examine new information about galaxies' locations and planned surveys, such as those from the European Space Agency's Euclid space telescope. This might help find the "detectable topological fingerprint" in the CMB, leading to more accurate results.

Oliver Philcox, a cosmologist at Columbia University who wasn't involved in the study, agreed that we still have a long way to go before figuring out how the world is put together. He also said it was hard to deny any options because the universe could be linked in many ways.

There is new evidence that the universe's size and form need to be examined again. But its shape could still be very complicated and look like a doughnut or a hall of mirrors. This study questions common ideas about space and time and shows interesting new ways to examine basic ideas about the universe.