Scientists' new finding turns understanding of the universe on its head (2025)

A new finding has challenged Einstein's theory of the Universe

Scientists might have gotten dark energy totally wrong. According to a new analysis, dark energy might be changing in a way that challenges our understanding of the cosmos.

Dark energy is the mysterious force causing our universe to expand faster over time. It makes up 70 per cent of our universe, but very little is known about this vast cosmic ingredient; we can't see, touch, or directly measure it.

Based on our current understanding of dark energy, if the universe is a balloon, dark energy is the air making it inflate faster and faster. It seems to be pushing everything in space apart, making galaxies move away from each other.

However, findings from the Dark Energy Spectroscopic Instrument (DESI) suggest that dark energy could be weakening. At first, scientists thought the initial finding was simply a blip in the data, the BBC reports. But the evidence has only become stronger.

"What we are seeing is deeply intriguing. It is exciting to think that we may be on the cusp of a major discovery about dark energy and the fundamental nature of our universe," said Prof Alexie Leauthaud-Harnett, a co-spokesperson for DESI and a cosmologist at the University of California, Santa Cruz.

The analysis looked at nearly 15 million galaxies across 11 billion years of cosmic time, creating the most detailed 3D map of the universe to date. The results suggest that dark energy has already reached its peak strength, and is now about 10 per cent weaker.

If confirmed, the results would have profound implications for theories about the evolution and fate of the universe. What's more, it would mean our current theories about the cosmos are completely wrong.

According to Einstein's theory, the universe isn't static and is, instead, expanding. It comes from the idea that the universe started from a small, hot, dense point around 13.8 billion years ago, known as the Big Bang.

"Now, DESI observations, combined with other probes, suggest the intriguing possibility that the density of dark energy may be evolving with cosmic time. If confirmed, this would represent a paradigm shift in our understanding of the universe," said Professor Ofer Lahav, a DESI collaborator and a member of its Executive Committee.

"If dark energy is constant, the universe would continue to expand at an accelerating rate forever. If it evolves with time, the fate of the universe is more uncertain," Prof Lahav added.

Expansion of the universe could instead eventually go into reverse in a "big crunch", where everything would collapse back together. It sounds extreme, and the evidence is far from conclusive, but the new evidence hints the expansion of the universe could slow down, stop, and then reverse in the distant future.

However, some researchers aren't entirely convinced by the data. Prof George Efstathiou of the University of Cambridge, who was not involved in the research, said: "My take-home from this analysis is that the…measurements do not yet provide decisive evidence for evolving dark energy. They may do as Desi accumulates more data."

That said, some skeptics have recently been converted by the evidence. "Extreme claims require extreme evidence,” said Prof John Peacock, a cosmologist at the University of Edinburgh and a DESI collaborator, who seemed unsure about the findings at a Royal Society meeting in 2024. "There’s almost nothing in science that I would bet my house on. But I would put £1,000 on this result," he added.

The findings were published in multiple papers on the preprint site arXiv. They are yet to be peer reviewed.