Cosmic fluctuations are the new big bang. Dark matter has long been seen as the invisible glue holding the galaxy together, stopping galaxies and clusters from drifting apart. But what if there’s a simpler explanation—one where gravity takes the lead? The idea of this hidden force first came from astronomer Fritz Zwicky, who used it to explain why galaxies in the Coma Cluster were moving faster than expected. Now, some researchers are challenging that view, suggesting dark matter might not be the full story after all.

Dark Matter not a thing anymore?

There’s no question that something strange is shaping the universe. As space keeps expanding, pushing into regions we can’t even see yet, there’s also something pulling matter in—keeping our galaxy from flying away or smashing into each other. That’s where dark energy and dark matter come in the galaxy. One stretches the cosmos; the other holds it together.

We call them “dark” because we can’t actually see them—we only know they exist because of how other things move around them. For years, scientists believed dark matter outweighed normal matter five times over. Now, scientists have been able to look into the past using an instrument that measures the dark energy – but how is this possible if we can’t see even in our own galaxy?

Cosmic fluctuations around our galaxy measured by DESI around 

Using 5,000 miniature robots inside a telescope stationed on a mountaintop, scientists have managed to peer 11 billion years into the past. That’s how far the light from distant galaxies had to travel before reaching the Dark Energy Spectroscopic Instrument (DESI). This tool is helping researchers map the universe and our galaxy as it once was and track how it has stretched and changed over time.

To explore that question, DESI has created the most detailed 3D map of the universe ever made. In just its first year, the team produced the most precise measurements yet of how fast the universe expanded in its early stages. According to data shared at scientific meetings in the U.S. and Italy, this is the first time researchers have pinned down the universe’s expansion history during that youthful phase with less than 1% uncertainty.

The project is managed by the Lawrence Berkeley National Laboratory, and according to DESI’s director, Michael Levi, the results so far align closely with our current understanding of the universe—known as the Lambda-CDM model. This model combines cold dark matter (CDM) with a cosmological constant (Lambda) to explain how matter slows expansion while dark energy speeds it up.

It’s too early to study the collected data?

Still, when scientists stacked DESI’s findings alongside previous data, they noticed some small differences that the current model doesn’t quite account for. It’s too early to say if these are statistical quirks or signs of something deeper—like a shift in how dark energy behaves over time in our galaxy. Either way, with several more years of data ahead, DESI is just getting started. The results could also help refine other key measurements, such as the Hubble constant and the mass of elusive particles like neutrinos.

DESI’s precision is out of this world

DESI has reached a level of precision that’s never been seen before. Looking back across 11 billion years of cosmic history, it has mapped the universe’s expansion with just a 0.5% margin of error. Even more impressive, for the period between 8 and 11 billion years ago—the universe’s distant past—it achieved a record precision of 0.82%. That kind of accuracy is notoriously hard to pull off. DESI has already outperformed the previous generation of surveys, like BOSS and eBOSS from the Sloan Digital Sky Survey, which took over ten years to reach similar results.