New theory to understand the origins of the Universe
PRESS RELEASE
15/07/2025
A team of scientists led by expert Raúl Jiménez, ICREA researcher at the University of Barcelona’s Institute of Cosmos Sciences (ICCUB), in collaboration with the University of Padua (Italy), has presented a revolutionary theory about the origins of the Universe. The study, published in the journal Physical Review Research, introduces a radical change in the understanding of the first moments after the Big Bang, without relying on the speculative assumptions that physicists have traditionally assumed.

Unravelling the mystery of the origins of the Universe

For decades, cosmologists have worked under the inflationary paradigm, a model that suggests that the Universe expanded extremely rapidly, in a fraction of a second, thus paving the way for everything we observe today. But this model includes too many adjustable parameters—the free parameters—which can be modified. Scientifically, this poses a problem, as it makes it difficult to know whether a model is truly predicting or simply adapting to the data.

In a significant breakthrough, the team has proposed a model in which the early Universe does not require any of these arbitrary parameters. Instead, it begins with a well-established cosmic state called De Sitter space, which is consistent with current observations of dark energy.

Gravitational waves: the key to understanding cosmic structure

The new model does not rely on hypothetical fields or particles such as inflation. It suggests that natural quantum fluctuations in space-time, gravitational waves, were sufficient to seed the small density differences that eventually gave rise to galaxies, stars, and planets. These ripples evolve non-linearly, interacting and generating complexity over time, allowing for verifiable predictions with real data.

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