This is a book review of The Universe in a Box: A New Cosmic History by Andrew Pontzen.
The Universe in a Box: A New Cosmic History, by Andrew Pontzen (Vintage), 2024 (first published 2023). Pp. 251, 19.8 × 13.8 cm. Price £12.99/$64.99 (paperback, ISBN978 1 529 92200 4).
A good move is to start with discussing weather and climate, something people are familiar with; the distinction between the two (details at a particular place and time as opposed to long-term large-scale trends) carries over into cosmological simulations, where the goal is to understand the general behaviour, not to mimic a specific scenario in detail. There are many interesting historical details on weather forecasting, climate simulations, chaos, and so on. The second chapter has a similar discussion with respect to simulations of the large-scale structure of the Universe and the roles of dark matter and dark energy in producing structures such as the cosmic web. Like the details of raindrops or even clouds in weather simulations, individual stars are much to small to be resolved in a cosmological simulation, leading to a discussion of sub-grid approximations, heuristical parameterizations designed to accomodate such small-scale phenomena into the simulation. An important application is the introduction of baryonic physics to refine more straightforward simulations containing only dark matter and dark energy. There is a balanced discussion between the critical claim that one gets out only what one puts in and the increased faith in such schemes when they successfully predict behaviour for which they were not designed. This is not a book about the details of simulations but about their purpose, their role within science, even the human side of them, presenting a balanced view by an expert on the subject.