This article contains affiliate links; if you click such a link and make a purchase, we may earn a commission.
“Hearst Magazines and AOL may earn commission or revenue on some items through these links.”
Here’s what you’ll learn when you read this story:
A new math model shows how very condensed spacetime could be part of general relativity.
The early universe and compact neutron stars both exemplify these exotic spacetimes.
Exotic spacetimes show extra “effective dimensions” that can help fit them into our understanding.
We experience the universe in four dimensions: three spatial dimensions and time. But what if that number isn’t fixed? What if the cosmos has a hidden extra dimension that only reveals itself under crushing pressure or blistering heat? A new study from Istanbul University proposes exactly that, and offers a mathematical framework to describe it.
The question matters because of the Big Bang. Cosmology’s biggest unsolved puzzle is what happened in the universe’s earliest moments, when all matter and energy were compressed into conditions so extreme that our standard physics crumble. It was only after the Big Bang that time and matter as we know them came into existence. Scientists seek analogies to those primordial conditions, such as extremely dense objects like black holes or neutron stars, so they can test their theories in at least an approximate way.
What connects all these exotic environments is a strange theoretical prediction: at very short distances or very high energies, spacetime may stop behaving as though it has exactly four dimensions. Scientists Lina Yıldız, Deha Kaykı, and Ertan Güdekli began their work, which appears now in European Physical Journal C, from the idea that different parts of our universe may appear to have more than the expected four “effective” dimensions precisely because of the extreme curvatures present in these regions. The researchers say that different parts of our universe may appear to us as having more than the expected “effective” four dimensions of length, width, depth, and time because of the “short distances or high energies” of these areas. They cite work going back to 2005 for this principle. Any areas showing strange dimensionality like this are edge cases of general relativity that must be interpreted into our existing body of physics knowledge.
So how do you build a theory that lets dimensions shift without wrecking everything else we know? The researchers’ answer draws on fractal geometry and a quantity called the Ricci scalar, which measures curvature in spacetime and how some pockets are different from the “flat space” around them. Using these tools, they constructed a new mathematical model in which the effective number of dimensions responds dynamically to local curvature. With a math expression in hand, the scientists and their peers can swap in and test this expression against other theories to see if the results make sense. And vitally, for areas that are less curved, the expression moves toward zero, meaning its results won’t clash with more well understood portions of physics.
This work shows that “high-curvature environments such as compact objects or the early Universe” can be understood using math that all extends from general relativity, rather than requiring us to add “an independent matter degree of freedom” with more parameters that must be accounted for. The model specifically highlights exotic scenarios without getting messy in the everyday universe we already understand well.
The math model also fits into the paradigm called scalar-tensor theory, or scalar-tensor model, without needing special additional math in order to play nicely. For now, the scientists concluded, their model has only been applied to the set of math where special curvatures “can be treated perturbatively,” or included in the field they’ve defined here as an addition to the usual four effective dimensions.
That’s a limited usage, but laying out both new terms and their domains gives other scientists a starting point. Cosmology requires a full Swiss Army knife of tools that you can swap and try in different scenarios without having to pick up a separate toolbox or Leatherman. Whoever wants to use the tiny scissors, in the spacetime curvature sense, will get to figure out how to make them.
So are there hidden dimensions lurking in our universe? According to this model, the answer is effectively yes, but only where spacetime curves hard enough to reveal them. In the gentle, flat space of everyday life, four dimensions are all you get. It’s only at the extremes—the Big Bang, a black hole’s core—that the universe appears to unfold extra room. The mystery isn’t fully solved, but now there’s a clean mathematical tool to keep prying it open.
You Might Also Like