The universe has no visible boundaries, and it is currently in constant expansion. That is the reason scientists came up with the concept of a domain wall: a transition area between two magnetic domains. Which means that if you, by any chance, reach the end of the universe, you might just change from one magnetic frequency to another. Due to our current technological limitations, we cannot actually reach this point of spacetime, but researchers might have enough fuel to turn this theoretical field into a reality.
The limitations in our universe: Expansion might end our progress
Many things in the universe we can only imagine and think about what they look like. For example, we can’t actually see a black hole, only the disk surrounding the big devourer and the deformation it causes in spacetime. With the tools NASA and other space agencies have, we are able to analyze many structures, and found an answer to what we experience daily.
Now, as the universe remains in a constant state of expansion, it is not easy to find the limit (or the domain wall). This means that we might never figure out the many secrets of the cosmos, as the constant state of expansion is also pushing galaxies, asteroids, black holes, stars, and planets further into space to fill empty regions. In the same time, the domain walls could mean something more.
The domain walls in the early stages of the universe
Domain walls are sheet-like structures that appear when a field’s symmetry breaks in a certain way. This isn’t an exotic idea – field theory suggests it could have happened quite often in the early universe. If the conditions were right, these walls might have linked together, stretching out into vast networks that, for a brief time, carried much of the universe’s energy before fading away.
A recent study led by Ferreira, posted on arXiv, explores what could have happened next. If these walls formed and then collapsed just fractions of a second after the big bang, they would have left behind faint ripples in spacetime itself. Astronomers have already hinted at detecting this kind of background “hum” of gravitational waves. The few walls that survived might have turned into black holes roughly the size of our sun – or even smaller ones that could make up the dark matter we still cannot see (but we think it’s there, like in this study)
The Standard Model in physics: The hole in the domain wall theory
The very idea of domain walls also points beyond the Standard Model of particle physics. That model describes nearly everything we know about fundamental particles and forces – except gravity – and still doesn’t quite make it. It assumes neutrinos have no mass, even though experiments say they do. And it cannot explain one of the deepest mysteries of all: why matter won out over antimatter in the early cosmos. Many attempts to go beyond the Standard Model focus on symmetry-breaking events. At extremely high energies, the universe starts off smooth and balanced, but as it cools and spreads out, that balance shatters.
The expansion of the universe simplified: It keeps going and cooling
In some of these theories, the same kind of breaking happens again, this time in the fabric of spacetime itself. The scalar field that marks the vacuum – the lowest possible energy state – can flip between two choices: a positive or a negative value. That split creates two distinct vacuum states as the cosmos keeps expanding and cooling. While proving the existence of this theoretical wall could also put an end to the dark matter and dark energy theory, it could also change what we know about the impact of ghost particles in the cosmos.