The Cosmic Puzzle: What Shape is Our Universe Really?
Have you ever looked up on a clear night and wondered what we can’t see beyond the most distant stars and galaxies, how the entire universe may be shaped? Spirituality, meet science!
The church where I most often worship is nature, particularly on clear, dark nights. It never ceases to fill me with awe.
But have you ever looked up on a clear night and wondered what we can’t see beyond the most distant stars and galaxies, how the entire universe may be shaped? Spirituality, meet science!
Around 2,500 years ago, humanity first grasped that our planet is round. But while we have a solid understanding of Earth’s shape, the shape of the universe remains far less clear. Earlier studies suggested the cosmos might have a simple shape, like the three-dimensional equivalent of a sphere or a plane.
However, this assumption might be incorrect, as cosmologists from the Collaboration for Observations, Models, and Predictions of Anomalies and Cosmic Topology (COMPACT) have suggested in their recent paper published in April of this year. They propose that the universe’s shape could be far more complex than previously thought.
At first glance, Earth itself appears flat because its radius is so vast that the curvature of its surface is almost imperceptible. To prove its spherical nature, one could walk straight ahead without turning—crossing mountains and oceans—and eventually return to the starting point.
Similarly, cosmologists seek clues to determine the shape of the universe. Instead of sending a spaceship on an impossible journey across the cosmos, they peer into the night sky, examining traces of the oldest light, the cosmic microwave background (CMB), that reaches us from the universe’s depths.
This ancient light dates back to about 300,000 years after the Big Bang. Before that, matter was so densely packed that photons (light) couldn’t travel freely. But as the universe expanded and cooled it became transparent, allowing photons to spread through space—a journey they continue to this day. By mapping out this cosmic background radiation, scientists gather essential clues about the universe’s shape.
The CMB provides a nearly uniform pattern of old light from all directions in the universe. If the universe’s curvature changed at any point, this radiation would appear less homogeneous than it does. Therefore, experts believed that the universe is either uniformly curved or completely flat.
Visualizing the universe’s shape can be challenging, so two-dimensional analogies help. Imagine the universe as a flat sheet of paper (no curvature), a three-dimensional counterpart of a spherical surface (positive curvature), or a saddle surface (negative curvature). Each case represents constant curvature throughout the universe.
However, these examples don’t fully capture the universe’s overall shape. For instance, space could have uniform curvature and still contain holes. Topology, a branch of mathematics, helps distinguish such possibilities by classifying geometric figures based on features like the number of holes, creating a catalog of shapes. Cosmologists aim to match the universe to one of these topologies.
Mathematicians have shown that there are infinitely many topologies for curved three-dimensional surfaces. If spacetime is indeed saddle-shaped or spherical, the universe could take on numerous, vastly different shapes.
However, current cosmological observations suggest a flat universe without curvature. If this is accurate, the search for the universe’s topology narrows significantly. In 2003, mathematician Grigori Perelman deduced that the catalog of flat three-dimensional surfaces comprises only 18 different categories.
Among these 18 potential shapes, one is the three-dimensional analog of a flat sheet of paper. Another possibility is that our cosmos could resemble a torus, or doughnut shape. Although a doughnut appears curved, it can be created by joining the opposite edges of a flat sheet of paper, first forming a tube, then bending it into a ring.
This analogy is useful. Imagine an ant walking on a doughnut-shaped surface. On a flat piece of paper, the ant walks straight and reappears on the opposite side when it crosses an edge, similar to the mobile game Snake. In three dimensions, you create a torus by gluing opposite sides of a cuboid. If the universe were torus-shaped, light shone into space would eventually return to its origin, creating observable loops.
However, these loops don’t align with current observations. If light looped through space, we would see multiple copies of the universe in the night sky. This hasn’t been observed, suggesting either the loops are much larger than our observable universe or the universe is shaped differently.
Yet, COMPACT’s recent findings indicate that previous research might have overlooked several topology (shape) variants. The team’s comparisons of the latest CMB data with various topologies revealed surprising results. They discovered that the absence of evidence for loops in the CMB is less definitive than previously thought. There could be other indicators in the CMB data pointing to complex topologies.
The researchers explored three specific flat-space topologies: a standard torus and two twisted variations of it. All three have holes, and the team confirmed that if the universe is a standard torus, the loops must be so vast that light hasn’t yet traveled their length.
However, the twisted shapes suggest that loops could be significantly shorter, potentially creating universe copies that differ from the original, making them harder to detect in CMB maps.
COMPACT’s findings suggest that the universe’s shape could be far more intricate than previously assumed, with profound implications. Understanding the universe’s topology isn’t just academic; it could unlock secrets of the early quantum processes after the Big Bang.
By delving deeper into the universe’s shape, we may uncover more about the fundamental workings of our cosmos, shedding light on its origins and evolution. Which, in its essence, is our origin.
I’m still thrilled, even after all these years, by looking up at the night sky; this understanding that the universe is so deeply complex only deepens my awe and faith in my belief that the universe itself is conscious or, at least, made of consciousness from one end to the other (regardless of shape).
Mr. Hartmann, thank you for this topic. The idea that the universe has a "shape" is a consequence of the fact that we humans live in a sociocultural world, created by language.
Our sense organs put us in physical contact with the physical world. Sight, sound, touch, temperature, taste/smell; these are the senses most of us are aware of. We have organs in our bodies which detect stimuli from the physical universe in which we exist. The sources of these stimuli are external to our physical bodies. This much is quite obvious to us all. There is one more sense that most of us do not think about very much, unless the individual has studied this sense in an academic setting, or unless one is adept at some physical activity. This sense is our kinesthetic sense. We can sense the positions of our limbs relative to the rest of our bodies without looking at them, hearing them, tasting/smelling them, or detecting them through touch. The stimuli for this sense come from within our bodies, not from without. Without this sense of kinesthesis we would not be able to learn to type, dance, run, jump, play tennis, etc.
We are able to describe the effects sensory stimuli have on our bodies through language. We can sharpen the sensory limits of our bodies with language and even describe the limits to other individuals as well. But there are great limitations on how well we can describe our kinesthetic experiences to other people. For example: I can tell you how to perform a kip-up on the still rings in a gymnasium, I can describe to you how to hit the ping pong ball back to your opponent, I can describe to you how to hit a golf ball toward the cup, I can describe to you how to type, or swim, etc. But the only way you will be able to learn to do all of these bodily activities is for you to actually move your body and detect the stimuli coming from the sensors located inside your body, not outside it. You must do it to learn it. This is kinesthesis in action. This description of kinesthetic sensory ability is perhaps a little tedious. But it must be included.
Now, let us move on to the apparently vast and largely unknowable universe in its "entirety." We think of the universe as having limits, boundaries, shapes, size because that is how our senses present the physical world to us. We have the linguistic ability to represent, or symbolically recreate the physical world with our symbols, primarily the symbols which make up our language. We can communicate with one another about the nature of our physical universe; its size, shape, boundaries, limits. We do this with language. There is no reason to believe that the universe actually is composed of boundaries, limits, shapes, or size. We sense the physical world as having these characteristics and we can talk about them. But they do not necessarily exist. Just because we can talk about a thing, or imagine a thing; does not mean that thing actually exists. I can imagine a unicorn and so can you. We can talk with one another about a unicorn. But, of course a unicorn does not exist. Many people believe there is a big daddy up there in the sky who created everything, knows everything and controls everything. But it just ain't so.
We must inevitably admit that there is no shape, limits, boundaries, or age to the universe. It is boundless. It is shapeless. It is timeless. It is limitless. It is absurd of us to speculate about these things. It has none of these things. It simply is. At this point it might be useful to talk about time. But we would be wasting our efforts; because time does not exist. It is a symbolic creation of human beings. That is the extent of its existence. It has no existence independent from us. The consideration of how and under what circumstances time comes into existence is a whole other topic.
A discussion of the nature of language might be appropriate here. But that too is another discussion.
Those who believe everything came into existence with "The Big Bang" are simply engaging in a sophisticated analogue of the first book of the old testament in the Judeo-Christian bible. I suggest that those religious individuals who object to my words here read the five proofs of the existence of a god found in the Summa Theologica of Thomas Aquinas, the brilliant, seminal philosophical father of the Christian church.
For myself, I prefer Fred Hoyle's interpretation of "The Big Bang." Hoyle believed there are some locations in the universe where there is an overabundance of matter. Under these conditions the matter spontaneously transforms into energy. There are some locations in the universe where there is an overabundance of energy. Under those conditions energy spontaneously transforms into matter. Various locations in the universe shift back and forth from one state to another in a pulsating manner. We live in a pulsating universe. A hint that this might be so can be found in the work of De Broglie. He said that anytime one physical thing moves relative to another thing, there is a pulsating wave in existence between them. In Physics books this is referred to as De Broglie waves. Astronomers and Cosmologists are fond of talking about how they can detect waves of some electromagnetic/gravitational kind which seem to be pulsating through the universe and their origins in space and time cannot be determined.
The late Fred Hoyle held the Plummerian Chair of Experimental Mathematics at Cambridge University. Mostly, he is remembered as an Astronomer and a Cosmologist