MOVING THREE WAYS IN A KNOTTY UNIVERSE
Right after the Big Bang, the young universe filled up with knots, producing the dimensions we live in, according to a new explanation of why the universe has 3 dimensions. The theory changes the story of how the universe formed.
Why are there only three physical dimensions? The answer may have something to do with spacetime knots in the early universe. No really.
Nick and Gabby want to meet in a restaurant in Manhattan, New York City. Nick explains that the restaurant is on the corner of 58th Street and 12th Avenue on the eighth floor. So, he has described their meeting place using three numbers – 58, 12, and 8 – but he might as well have used the degrees of latitude and longitude plus height. The location of all points in space can be determined by means of those three numbers – the world is 3D.
The three spatial dimensions of the universe are so obvious to us that scientists have rarely tried to find out why it is organized in this way, but physicists have developed a new theory that explains it: the universe has three dimensions, as it is based on an exploding network of entangled knots.
The universe loses dimensions
Today, physicists’ understanding of the Big Bang is based on the superstring theory, according to which all mass and energy in the universe right after the Big Bang consisted of tiny, vibrating superstrings, which existed in 10 spatial dimensions. Subsequently, the universe experienced an ultrafast expansion known as inflation, during which the young universe grew from the size of an electron to the volume of a football in a split second. When the inflation was over, the universe only had three major, spatial dimensions.
The passing from 10 to 3D during the expansion is consistent with physicists’ Big Bang model, but the model does not include any triggering factor, nor does it explain how it happened. In 2012, five physicists from Europe and the US began to ponder the question, and now they have come up with an answer.
The physicists’ new theory is based on traditional theories about the Big Bang combined with the knot theory, according to which mathematical knots can only exist in 3D. The scientists were inspired by the primordial soup of the universe, which formed after the inflation and existed one microsecond after the Big Bang. The primordial soup consisted of equal quantities of quarks and antiquarks, which flowed about a soup of force particles known as gluons. In the present expanded and cooled universe, gluons bind quarks into protons and neutrons, and so hold atomic cores together. But in the primordial soup, all matter was billions of degrees hot, and in the extreme heat, the building blocks could not form, so the quarks were free. Instead, brief gluon bindings formed between quarks and antiquarks. When matter and antimatter encountered, the particles destroyed each other and were converted into radiation. During the destruction, quark and antiquark moved away from each other, so the gluon "rubber band" between them was stretched to its bursting point, burst, and was converted into radiation. The destruction released sufficient energy to produce a new pair of one quark and one antiquark linked by a gluon rubber band. The process was repeated with myriads of mesons.
Knots organised the world
In the new theory, it was not sufficient that a primordial soup developed after the inflation, so the theory includes a similar substance, in which destruction of quarks and antiquarks happened before the inflation, when the universe was smaller and much warmer than in the primordial soup. The physicists thought that if the myriads of burst gluon rubber bands had time to entangle into knots, before they were converted into radiation, the rubber bands would be stabilized and briefly survive the destruction of the particles.
According to the physicists' calculations, the burst rubber bands entangled into a complex, common network of knots. The entanglement happened almost automatically, as billions of gluon rubber bands existed in the young universe, which was the size of an electron.
If the universe right after the Big Bang primarily consisted of a network of gluon rubber bands, the structure would contain huge quantities of energy. The network would only be able to remain stable for a split second, before collapsing in an explo-sion that released all the energy of the network. The explosion powered the universe’s extreme expansion during the inflation, and because the knot network was 3D in itself, it inflated a 3D space.
Knots could be dark energy
The five physicists aim to find out exactly how the repulsive energy triggered by the knot network in the explosion functioned as an opponent of gravity, enabling the uni-verse to expand. Both traditional theories and the new theory predict that the type of repulsive energy that powered the inflation is the same that has made the universe’s expansion accelerate for the past six billion years – i.e. dark energy. So, the scientists aim to find out if the knot network could also be the driving force behind dark energy.
In 2015, scientists managed to detect the first gravitational waves in space. Gravitational waves are emitted, when large masses are accelerated fast through space, which happened during the inflation, when the entire universe expanded at a speed faster than that of light. In a few decades, scientists’ equipment may be able to detect gravitational waves from the inflation of the universe. If so, the marks left by the waves might reveal where the expanding force came from. And then we would know if the entangled knot network of the new theory is the reason why Gabby and Nick only need three numbers to find each other. Well, there is a fourth number of course: the time they hope to meet. But that's a whole other story...