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A new cosmological model suggests that the early Universe may have developed the first seeds of galaxies and other large-scale structures without needing the hypothetical scalar field commonly used in explanations of inflation (or early rapid expansion).
Cosmology is the study of the origin, evolution and large-scale structure of the Universe. For decades, cosmologists have worked with the inflationary paradigm, which says that the Universe expanded extremely rapidly in a fraction of a second shortly after its beginning. This idea helps explain how small differences in density in the young Universe could eventually grow into galaxies, galaxy clusters and other structures seen today.
Inflation is not a single model. There are many versions, and they can contain adjustable values known as free parameters. These parameters can be changed within a model to match observations. This creates a scientific problem because it can make it harder to tell whether a model is genuinely predicting what scientists will observe or simply being adjusted to fit existing data.
The new proposal takes a different approach. It begins with a state known as De Sitter space, which describes space-time undergoing rapid expansion. De Sitter space is also relevant to current descriptions of dark energy, which is linked to the observed accelerated expansion of the Universe.
