strophysicists say the universe started with the Big Bang, during which
space and time as we know them were created and flattened out, so to
speak, forming the spacetime continuum we all know and love.
But what could have caused the Big Bang? Maybe we shouldn’t dismiss the possibility of a misprogrammed time machine somewhere in the distant future. If so, the first words ever spoken probably were not “Let there be light” but “Hey, watch this!”
They amount to the same thing. A time machine (or more realistically, an experiment at creating a closed timelike curve) might have feedback effects. If something as small as a dust particle went into the past by even a millionth of a second, it would re-enter the curve and the mass would increase exponentially until the lab turned into an enormously concentrated black hole.
That would obviously put a damper on your grant renewal, and such an event is obviously highly speculative and is beyond any current theories. But we can be sure that something interesting would happen. Perhaps at such high energies, mass, energy, and spacetime would be unified and do something unexpected. Some physicists even speculate that, in effect, matter could change into geometry.
Geometrogenesis
This seems to be a niche topic with only a handful of people studying it. Their current thinking is that geometrogenesis could be a condensation of a higher dimensional spacetime that has a high degree of symmetry. One model for this is called quantum graphity, originally a pun on the term ‘quantum gravity’ but at the moment a leading contender for a solution to the question of how to describe the generation of space.
Quantum graphity This graph depicts a toy version of some object described as a non-geometric phase at high temperature. As the connections between nodes are rearranged, the dimensionality is reduced and the energy is released in the Big Bang (Source: Jakub Mielczarek at arXiv)
This is a philosophical question as much as a scientific one because all the current equations in physics implicitly assume a pre-existing background. As Wilkinson and Greentree say:
A quantum theory with no inherent notion of geometry cannot be formulated with respect to a fixed manifold, nor can it make use of the usual global symmetries.
The general idea is that at the instant of the Big Bang, only one highly unstable high temperature thing existed. All matter, energy, and spacetime had to come from it by a process of symmetry breaking or phase change as it fell apart. As the physicists put it, the graph would lower its energy by creating matter.
There are several competing models, but they all have the same property: a ‘graph’ with vertices that represent something in a higher dimensional object. As the number of vertices increases, the graph becomes more unstable and the critical temperature of the phase transition goes to zero, which means it automatically disintegrates with a big release of stuff, including space and time.
If it happened at T=0, physicists say, it would mean that it couldn’t be a thermal transition but a quantum one. Jakub Mielczarek says this is consistent with the causal dynamical triangulation theory, a developing new theory that models events in time as connections between quantum objects and has a built-in notion of causality and time.
Mielczarek says gravity can be in three different phases:
A phase = vanishing interaction between adjacent time slices
B phase = crumpled phase, the high temperature phase in quantum graphity
C phase = four-dimensional de Sitter space which is like the one we’re in, with normal gravity. It reduces to 2 dimensions at Planck scale.
The high temperature phase B undergoes a phase transition to the low temperature phase C, during which the elementary chunks-o’-space get connected to each other. Wilkinson and Greentree like this idea and speculate that as the graph lowers its energy, it doesn’t produce a continuum but “distinct grains” that then knit together, as if spacetime automatically heals itself.
A more recent paper by this author and co-workers says that predictions from a competing model known as minisuperspace agree with the causal dynamical triangulations model. Another group says quantum graphity may provide an emergent concept of locality, which is a feature of classical physics.
Phase transitions
This is all very appealing because in condensed matter physics, which we mortals call ‘chemistry,’ a phase transition often causes a change in symmetry. When water freezes, for example, it undergoes a phase change from liquid to a solid where the molecules are packed in a regular symmetric array.
It’s all quite speculative, but so far it’s the closest thing we have to a plausible explanation of how spacetime could be created. But I like my theory better.
Whatever evidence could support these ideas might be found in the cosmic microwave background. For instance, we might find evidence of domain boundary defects. One physicist suggests that a good theory should predict, and maybe explain, the speed of light. One piece of evidence we’re unlikely to find, however, is a voice hidden in the cosmic microwave background saying “Hold mah beer!” echoing through space for all eternity.
It might be improbable, but it would be a beautiful finding. It would let us conclude that the Big Bang was somebody else’s fault. It’s the ultimate goal of astrophysics: to find somebody to blame for the universe.
sep 11 2026, 5:35 am
