A third option, asymptotically safe gravity, goes back still further, to 1976. It was suggested by Steven Weinberg, one of the Standard Model’s chief architects. A natural way to develop a theory of quantum gravity is to add gravitons to the model. Unfortunately, this approach got nowhere, because when the interactions of the putative particles were calculated at higher energies, the maths seemed to become nonsensical. However, Weinberg, who died in July, argued that this apparent breakdown would go away (in maths speak, the calculations would be “asymptotically safe”) if sufficiently powerful machines were used to do the calculating.
- —The Economist, 28 August 2021