Why cosmology is more than a theory

Edwin Hubble found that distant galaxies travel away from Earth faster than nearer ones. Credit: New York Public Library/SPL Universe: A Guide to Everything Helge Kragh Reaktion (2026) What is the Universe? Should we think of it as a thing or a set of ideas? Acclaimed historian of science Helge Kragh grapples with such deep questions in his latest work, which he acknowledges is “a small book about a big subject”. Universe is a distillation of Kragh’s many writings on the history of cosmology. Rather than describing what the Universe looks like, his focus is on how conceptual models have evolved , from those of the ancient Greeks to today’s. Presenting these frameworks in simple, dramatic and refreshing ways, his account is lucid, coherent and captivating. The expanding Universe — do ongoing tensions leave room for new physics? The Universe, Kragh explains, refers to “everything that has, has had or will have a physical existence” and includes “all kinds of matter and energy as well as the totality of space and time”. Terms such as cosmos and cosmology — as well as cosmetics and cosmetology — are rooted in the Greek word kosmos , which refers to order, harmony and beauty. The Universe is not an object, Kragh reasons, because one must be able to stand outside an object to fully appreciate its nature. Furthermore, it transcends observation. …