Theoretical physicists have proposed a new view of gravity that explains one of the deepest paradoxes of cosmology: why the Universe becomes increasingly structured even though the laws of thermodynamics require a steady growth of disorder. The study was published in the journal Physical Review D.

The second law of thermodynamics states that in a closed system, entropy — a measure of disorder — always increases. The Universe as a whole moves toward equilibrium and uniformity. In practice, however, we see the opposite: from an initially almost uniform cloud of matter emerged galaxies, stars, planets, and life. This apparent contradiction has long troubled physicists.

The authors of the new work showed that the key to solving the puzzle lies in the expansion of space itself. As the Universe expands, it constantly creates “new room” — volume in which matter can organize into structures without violating the overall growth of entropy. In other words, local order — stars, planets, biospheres — is possible precisely because the total volume of the Universe grows faster than it has time to “mix.”

Within the framework of the new theory, gravity is viewed not merely as the curvature of spacetime in Einstein’s sense, but as the driving force that enables this structuring. Gravity gathers matter into clumps, lowering local entropy at the cost of increasing it in the rest of space — in the form of radiation and heat. The expansion of the Universe serves as a “buffer,” without which this process would be impossible.

The authors emphasize that their approach does not contradict general relativity, but builds on top of it. According to the scientists, this framework may prove useful in the search for a unified quantum theory of gravity — one of the main unsolved problems of modern theoretical physics.