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For years, dark energy has puzzled scientists worldwide. It drives the universe's expansion, yet its true nature remains unknown. Now, new evidence suggests it might be changing—something that could reshape what we know about space and time.
Astronomers have long accepted that dark energy remains constant. However, researchers at the Dark Energy Spectroscopic Instrument (DESI) are seeing hints of variation. This unexpected shift could challenge theories dating back to Albert Einstein’s work.
Prof Ofer Lahav from University College London called it a "dramatic moment" for astronomy. "We may be witnessing a shift in our understanding of the universe," he told BBC News.
Unexpected Findings Grow Stronger
Dark energy was first discovered in 1998. Scientists then realised that instead of slowing down, the universe’s expansion was accelerating. The force behind it remained unknown, so they named it dark energy.
DESI, a project at the Kitt Peak National Observatory in Arizona, is helping astronomers measure this energy. The instrument, with 5,000 robotic optical fibres, scans galaxies at high speed.
Last year, DESI researchers noticed a small irregularity in dark energy’s strength. Many believed it was a mistake in the data. Instead, the anomaly has only grown.
“The evidence is stronger now than before,” said Prof Seshadri Nadathur from the University of Portsmouth. “We’ve run many additional tests, and the results still hold.”
Scotland’s Astronomer Royal, Prof Catherine Heymans, also weighed in. “Dark energy appears to be even stranger than we thought,” she said.
What Happens Next?
Scientists remain cautious. The data has not yet reached the level required for a confirmed discovery. However, it has sparked curiosity across the scientific community.
"If this is correct, we need a new theory," said Prof Lahav. "That makes this research so exciting."
DESI will continue its mission, aiming to measure 50 million galaxies over two years. Meanwhile, the European Space Agency’s Euclid telescope, launched in 2023, will provide even deeper insights.
"We're letting the universe tell us its secrets," said Andrei Cuceu from Lawrence Berkeley National Lab. "It might be more complex than we imagined."
The DESI project includes over 900 scientists from 70 global institutions. UK-based researchers from Durham, UCL, and Portsmouth are closely involved. Their findings could reshape how we see the universe.
