No Dark Energy Needed? New Gravity Theory Could Explain Why the Universe Is Expanding

For more than a century, Albert Einstein’s theory of general relativity has been the foundation of our understanding of gravity. According to Einstein, gravity is not simply a force pulling objects together. Instead, massive objects like stars, planets, and galaxies bend the fabric of spacetime — an invisible four-dimensional structure that shapes how objects move through the universe.

This revolutionary idea transformed physics and successfully explained many cosmic phenomena, including the motion of planets, black holes, and the bending of light around massive objects. However, despite its incredible success, general relativity still leaves some major mysteries unanswered.

One of the biggest challenges is the cosmological constant problem — a strange disagreement between what scientists observe about the energy of empty space and what quantum theories predict. According to calculations from quantum physics, the energy of empty space should be enormously larger than what astronomers actually measure. This mismatch remains one of the deepest unsolved problems in modern physics.

Now, researchers from Imperial College London have proposed a completely different way of looking at gravity. Instead of starting with Einstein’s equations, they explored whether gravity could emerge from the principles of thermodynamics — the science that explains heat, energy, and their transformations.

Their work, published in Physical Review Letters, builds on a groundbreaking idea introduced by theoretical physicist Ted Jacobson in 1995. Jacobson showed that Einstein’s theory of gravity could be connected to thermodynamics by treating spacetime itself as something with temperature and entropy.

Rather than viewing gravity as a fundamental force, his approach suggested that gravity might be an emerging phenomenon — something that appears from deeper physical processes, similar to how temperature emerges from the collective movement of atoms.

A New Approach: Creating Gravity From Thermodynamics

The new study was led by João Magueijo along with Ph.D. researcher Ray Isichei. Their goal was not to modify existing gravity theories but to ask a more fundamental question:

What kind of gravity theory would appear if scientists started only from thermodynamic principles?

Magueijo had been interested in Jacobson’s work for decades. Instead of forcing existing theories of gravity into a thermodynamic framework, he wanted to reverse the process and allow a new theory of gravity to naturally emerge.

The researchers compared gravity with a thermodynamic process known as the Otto cycle — the process used to describe how traditional gasoline engines operate.

In ordinary thermodynamics, heat transfer is not the only factor involved. Other processes can occur, such as expansion, compression, chemical reactions, and work being performed. The researchers wondered what would happen if gravity also involved additional processes beyond simple energy exchange.

“We added this missing ‘something else’ without assuming what the final result would be,” Magueijo explained.

This approach led to a surprising possibility: a new gravitational theory where matter and energy are not always perfectly conserved.

A Challenge to One of Physics’ Most Important Rules

The conservation of energy and matter is one of the strongest principles in physics. The idea that energy cannot be created or destroyed has guided scientific understanding for centuries.

When the researchers found that their model allowed matter and energy to change, it initially seemed like a major problem.

A theory that breaks such a fundamental rule would normally be rejected. However, the scientists discovered something unexpected when they applied their model to the entire universe.

The modified conservation law could explain the accelerated expansion of the universe without requiring mysterious substances like dark energy or the cosmological constant.

For decades, scientists have believed that the universe’s expansion is speeding up because of dark energy — an unknown form of energy thought to make up most of the cosmos. But despite extensive research, dark energy has never been directly detected.

The new theory suggests that the acceleration of the universe might instead come from changes in the way matter and energy behave on cosmic scales.

Could Matter Itself Drive the Expansion of the Universe?

According to standard physics, ordinary matter should slow down the expansion of the universe because gravity pulls matter together. However, this assumption depends on traditional conservation laws remaining unchanged.

In this new model, if matter is continuously created through modified conservation rules, ordinary matter could potentially contribute to the expansion of the universe instead of slowing it down.

This creates a completely different picture of cosmic evolution — one where the universe’s acceleration does not require an invisible energy source.

If correct, this idea could reshape how scientists think about some of the biggest mysteries in cosmology.

A New Direction for Understanding Gravity

The study does not replace Einstein’s theory yet. General relativity remains one of the most accurately tested theories in science. Instead, this research offers a new theoretical possibility: that Einstein’s gravity may be a result of deeper thermodynamic processes.

The idea is still in its early stages and requires extensive testing. A successful theory must match observations of the universe, including galaxy movements, cosmic expansion, gravitational effects, and other astronomical measurements.

Modern cosmology has entered an era where theories must survive comparison with enormous amounts of precise data. Any new idea about gravity must prove itself against observations.

The researchers now plan to study whether their model can accurately reproduce known cosmic behavior and whether it makes predictions that can be tested.

The Future of Gravity Research

For centuries, scientists have searched for a deeper understanding of gravity. Newton described it as a force between objects. Einstein revealed it as the curvature of spacetime. Now, researchers are exploring whether gravity may be something even more fundamental — a phenomenon connected to the hidden thermodynamic nature of the universe.

If this new approach succeeds, it could provide answers to some of the biggest questions in physics, including why the universe is expanding faster than expected and why the energy of empty space does not match theoretical predictions.

The universe may not only be made of matter, energy, and spacetime. It may also be governed by deeper principles where gravity, heat, and information are connected in ways we are only beginning to understand.

Reference: Raymond Isichei et al, Lorentz Violation in Emergent Gravity and Its Cosmological Consequences, Physical Review Letters (2026). DOI: 10.1103/tvmx-qk3k.