Ever since Albert Einstein showed that space and time can be dented, warped, and stretched out of shape like an old mattress in a cheap motel, cosmologists have looked up and wondered what kind of food our universe most resembles in shape.
Is it shaped like an infinite Pringle, forever bending upward and outward into eternity? Could it be a pizza, perfectly flat if you ignore the bumps of galactic pepperoni and cheesy dark matter? Maybe it’s more like a spicy meatball, bending backwards until it meets itself on all sides.
Or maybe it’s more like a donut that forms closed loops in multiple dimensions. An international team of cosmologists who recently formed a group called COMPACT Collaboration have analyzed the remaining glow from the Big Bang and concluded that nothing in the patterns rules out such a cosmic landscape, if it turns the right way.
Since “squiggly cosmic doughnut” isn’t (yet) a bona fide mathematical term, the researchers use the term 3-torus to describe the mind-boggling possibility of stabbing yourself in the back of the head with a stick made of tens of billions of particles. light years long, no matter which way you look.
Yes, you read that correctly. Imagined another way, our universe could be one giant fairground attraction center, where instead of a series of mirrors, space-time bends in all directions, allowing you – in theory – to see your own back pockets if you squint hard enough.
It’s an attractive possibility that has been revisited over the years, and not just because of physicists’ preference for gourmet desserts. Exotic shapes on a large scale could lead us to the physics of how our universe emerged from a seed of… well, something.
About 13.8 billion years ago, everything we can see (and everything we can’t see, for that matter) was crammed into an impossibly small space that science has yet to describe, requiring a mix of quantum physics and general relativity that we have yet to understand. to have. to land on.
What can What can be described are the moments when space stretched and the material within it cooled. At some point, the universe expanded enough to allow some of its electromagnetic radiation to escape the dense mass of electrons and solidifying atomic nuclei.
A fraction of those free photons have since managed to avoid collisions, humming along happily as expanding space has stretched the light into long, cool noodles of microwave radiation.
This low-energy ‘glow’ is called the cosmic microwave background (CMB). Mapping subtle variations in the CMB’s glow can give us a rough idea of ​​what the first moments of expansion looked like. While this is useful for some models, the scale and patterns on the map depend largely on how the space is formed, leaving other theories open.
If we live in a giant pizza? These fluctuations should all accurately reflect the same scale. Do you have a Pringle universe? Light can bend in such a way that the variations are smaller than they appear. Meatball? The light could have blown up.
And if it’s a donut? The universe would be topologically flat, like a pizza, only with repeating patterns that could point to phenomena that break radically new ground in our quest to understand the origins of everything.
Unfortunately, no clear signs of these closed loops of space and time can yet be seen in the CMB. Before you shout “case closed and where’s my side of galactic garlic bread?”, members of the COMPACT Collaboration argue that we shouldn’t be so hasty.
In their first publication, the team states that some exotically shaped universes, based on the more distorted shapes of a 3-torus, are still compatible with the CMB.
While the everyday donut runs into trouble at certain scales, we cannot so easily discard versions of the torus that warp light in such a way that patterns distort correlation but are still preserved.
Looking for those correlations might reveal exotic features of the overall shape of our universe, perhaps with twists and curves that require new physics to explain.
Perhaps Homer Simpson’s theory was that the cartoon Stephen Hawking so intrigued wasn’t so absurd after all.
This research was published in Physical Assessment Letters.