Emergent space-time

It is an exciting time to be a physicist. There are a lot of puzzles that need investigating about the cosmos God has put us in. We don’t know, for example, what dark matter and energy are, yet they make up the most significant portion of our world. Likewise, the two overarching theoretical frameworks in physics – Einstein’s relativity and quantum theory – are strongly supported but appear to be in conflict. 

Two theories   

In his theory of relativity, Einstein combined time and space into a four-dimensional understanding of reality. Time becomes relative to the space framework of the observer and may be different for two people who are moving relative to each other (though this effect only becomes evident when the movement approaches the speed of light). Many tests have confirmed the predictions of relativity, the existence of gravitational waves being only the latest. But gravity, which is central to relativity, seems to fall outside our understanding of quantum theory.

Quantum theory also has strong support but is usually studied at a microscopic scale. I don’t claim to understand the theory, but I am convinced by the phenomena that it explains, like the dual nature of light being both a particle and a wave, depending on how it is studied. The theory leads to many counterintuitive conclusions, like the possibility of particles being connected even when they are vast distances apart – quantum entanglement.

For the last hundred years, physicists have tried to determine how these two very small and very large theories fit together. One attempt attracting considerable attention is the suggestion that space-time is an emergent property of the quantum world.

The dual nature of tea  

An example of emergent reality can be seen in a cup of tea. At one level, tea is a liquid that can be poured from the cup down the drain. At another level – the molecular – tea is a combination of water molecules and flavour molecules whose average motion determines the temperature of the fluid; faster motion of these molecules means hotter or boiling tea. Boiling is only explained at the molecular level. However, individual molecule motion is not the easiest way to understand pouring tea; this is better understood in terms of fluid mechanics. Thus, we can say the fluid nature of tea is an emergent property of the motion of the tea molecules.

Similarly, space-time might be an emergent property of the quantum nature of the cosmos. In this understanding, space-time may be grounded in the quantum behaviour of its very small components, like the fluid nature of tea, which is based on its molecular structure. Physicists are determining if the quantum level can be mapped onto the space-time level as the molecular can be mapped onto the fluid.

Fresh every morning 

God’s creation is rich and mysterious and yet full of these types of emergent examples. I wonder if we can think of our understanding of God emerging from the individual stories we find in Scripture. We know God loves us because of the way our Lord acts in the Old and New Testaments. But God’s love is more than the individual acts. It is new every morning.