Did the universe begin as a slender thread?
A new framework for the universe's formation suggests that it began as a single thready line, then evolved into a plane, and only then the three-dimensional space we now inhabit. This could simplify sticky cosmological questions, including dark matter and gravity waves.
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A shift from one to two, and then to three dimensions would have occurred long before a cosmic stopwatch recorded the first full second of the universe's existence.Skip to next paragraph
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Why the universe would have started as a one-dimensional structure, or what took place during the transitions as new dimensions emerged, have yet to be worked out, Stojkovic acknowledges.
But, he says, if one could view the event from a distance and in excruciatingly slow motion, his calculations suggest that the big bang initially yielded a single rapidly-stretching one-dimensional thread. That energetic thread snaked back and forth across itself, forming a kind of two-dimensional fabric. With time, that fabric finally yielded the three-dimensional structure that humans experience.
The size scale of the nascent universe during this process, whose progress took place within the first trillionth of a second following the big bang, would have been vanishingly small.
This approach to viewing these early actions resolves several longstanding issues that have been vexing physicists and cosmologists, Stojkovic says.
With each step backward in dimension, the mathematical gap – between gravity as Albert Einstein described it in his theory of general relativity and as quantum mechanics would try to describe it – narrows until, in a one-dimensional fledgling universe, it vanishes, he says.
Likewise, general relativity can yield a dark-energy-like expansion of the universe without having to invoke a so-called cosmological constant, which Einstein did and later retracted. Merely have general relativity play out in four dimensions, rather than three, Stojkovic says.
Finally, in a one-dimensional early universe, no one needs need to fine-tune values of the mass for the Higgs boson – an object physicists are trying to detect at CERN and whose interactions are said to give all other particles their mass – to get the equations describing the particle to fall within the standard model.
At this stage, Stojkovic says, the notion of vanishing dimensions as one looks deeper into the universe's fiery beginning falls far short of a full-blown theory.
But within the realm of physics and cosmology, it's "a respectable proposal," says Sean Carroll, a cosmologist at CalTech in Pasadena, whose own preferred picture of the universe's evolution starts with more dimensions at the outset that disappear over time.
That picture, however, is a bit too complicated for Stojkivic's sense of scientific aesthetics, where if several ideas can explain the available experimental data, make a beeline for the simplest one. Whether simplicity reigns as Stojkovic and colleagues work to fill out their framework remains to be seen. But at the least, it's efficient, he says. It appears to solve several longstanding conundrums simultaneously. And seems far simpler than invoking a universe that started out with 11 dimensions and an unfamiliar zoo of additional subatomic particles.
Stojkivic's aesthetic echoes that of Roger Penrose, renowned Oxford University physicist and cosmologist, who once wrote, "A beautiful idea has a much greater chance of being a correct idea than an ugly one."