Einstein predicted how gravity would work on the largest scales. And he was right, new research suggests

When Albert Einstein introduced the theory of general relativity in 1915, it changed the way we view the universe. His model of gravity showed that Newtonian gravity, which has dominated astronomy and physics for more than three centuries, is only an approximation of a more subtle and elegant model.

Einstein showed that gravity is not just a force, but rather the basis of the structure of the universe. According to Einstein, gravity defines the very structure of space and time.

But over the past century, we’ve learned more about the universe than even Einstein could have imagined. While some of our observations, such as gravitational lensing, clearly support general relativity, others seem to poke holes in the model. The rotational motion of galaxies does not match the predictions of gravity alone, leading astronomers to introduce dark matter.

The expansion of the universe is not constant but is accelerating, suggesting the existence of dark energy. For some astronomers, this signals the need for a new model. One that could explain the movements of stars and galaxies without the need for dark matter, which remains undetected in the laboratory. The most popular alternatives focus on modified gravity theory.

The standard model of cosmology is known as the LCDM model. The L in lambda is the symbol used in general relativity to represent the rate of expansion of the universe and represents dark energy. CDM, on the other hand, stands for cold dark matter. This model describes an expanding universe that began as a hot, dense state about 13.78 billion years ago.

It is a universe composed of about 5% normal matter, 25% dark matter, and 70% dark energy. Currently, this is the model best supported by observational evidence. The modified gravity model has a big mountain to climb. To defeat LCDM, we need to consider everything it predicts and eliminate the need for dark matter and energy.

This year, the slope has become even steeper. A series of publications released by the Dark Energy Spectrometer (DESI) collaboration and posted to the arXiv preprint server confirm that the standard cosmology model perfectly matches Einstein’s model. The DESI survey mapped approximately 6 million galaxies over 11 billion years of cosmic time, allowing astronomers to study not only how galaxies cluster, but also how that clustering changes over time. Now you can check if it does. This is the largest 3D map of the universe ever created.

The LCDM model predicts the structure of the universe very closely. If dark energy were a kind of repulsive force rather than an inherent property of spacetime, clustering would evolve differently than observed. If dark matter were a phantom of modified gravity, the magnitude of galaxy clustering would be different.

This latest study shows in clear detail that the modified gravity model is untenable. This result strongly constrains which modified gravity models are possible and rules out many of the currently proposed models. Based on these new results, we found that Einstein’s standard cosmological model of gravity, dark matter, and dark energy is the one that best fits the observed universe.

There are still mysteries to solve, the most important being the Hubble tension problem. Perhaps a newly revised gravity model will solve this mystery and finally defeat Einstein, but for now, this wild-haired genius remains king of the hill.