One of the deepest tensions in modern physics is the apparent contradiction between the second law of thermodynamics and the existence of order. The second law states that entropy — often loosely described as disorder — must always increase in an isolated system. Yet the Universe managed to produce galaxies, stars, planets, and even life — some of the most intricately organized structures known. How can both be true?
A new theoretical study by Professor Ginestra Bianconi, a mathematician at Queen Mary University of London, offers a compelling answer. Working within a framework called Gravity from Entropy (GfE), Bianconi shows that the Universe can become more complex locally while total entropy continues to rise globally — and that gravity itself may be the key to understanding this paradox.
The GfE theory departs from the traditional view of gravity as a fundamental force. Instead, it proposes that gravity emerges from the "informational tension" between the true metric of spacetime and a second metric induced by the presence of matter fields and curvature. In this view, gravity is not an architect but a bookkeeper — a tally of the difference between two ways of measuring spacetime geometry.
Published in Physical Review D, the analysis reveals a crucial distinction. As the Universe expands, its total entropy continues to increase, satisfying the second law. However, because space itself is growing, the entropy per unit of volume actually decreases. This creates a gradient — a thermodynamic opportunity for matter to organize into denser, more complex configurations. Galaxies condense, stars ignite, planets form, and eventually, life emerges, all within a universe that remains thermodynamically consistent.
The theory also offers a fresh perspective on dark energy. Under the GfE framework, the equations of general relativity are recovered at low energies and low curvature, but under more extreme conditions, a dynamically changing dark energy term appears. Unlike the cosmological constant — which is fixed — this evolving dark energy could potentially be tested through astronomical observations of cosmic expansion.
The work builds on the legacy of Jacob Bekenstein and Stephen Hawking, who in the 1970s showed that black holes have entropy and emit thermal radiation, revealing a deep connection between gravity, information, and thermodynamics. GfE extends this relationship to the entire cosmos, suggesting that gravity may not be a fundamental force at all, but an emergent phenomenon written in the language of information and entropy.
If confirmed, the theory would represent a major step toward reconciling quantum mechanics with general relativity — the holy grail of modern theoretical physics — and would fundamentally reshape our understanding of why the Universe is the way it is.