NEW YORK — Scientists are delving deeper into the enigmatic force known as dark energy, with the fate of the universe at stake. This force is not only immense—comprising nearly 70% of the cosmos—but also incredibly influential, propelling stars and galaxies to separate from each other at accelerating speeds.
The scientific community is making strides towards understanding how dark energy operates, raising a crucial question: Is this force a steadfast constant, as traditionally believed, or is it diminishing—a novel possibility suggested last year?
During a presentation at the American Physical Society meeting on Wednesday, new findings lent some support to the notion that dark energy might be waning. However, certainty remains elusive, and the implications for our broader comprehension of the universe are yet to be fully discerned.
This progress is due to an international research effort crafting a three-dimensional map, tracing the dispersal and clustering of galaxies over 11 billion years. By meticulously observing galaxy movements, scientists can garner insights into the forces influencing them.
The Dark Energy Spectroscopic Instrument, a key component of this research, initially analyzed 6 million galaxies and quasars, increasing the count to nearly 15 million with new data. Additional measurements involving exploding stars, light remnants from the early universe, and galaxy shape distortions have further supported last year’s idea that dark energy could be waning.
Bhuvnesh Jain, a cosmologist from the University of Pennsylvania not directly involved in the study, notes, “We’re shifting from a startling discovery to a moment where we might need to rethink cosmology entirely.”
Although the notion that dark energy might be weakening gains traction, it’s not yet time to discard the idea of its constancy. The current findings still fall short of the rigorous statistical proof required in physics. The research team aims to map 50 million galaxies and quasars by 2026’s end, and other global projects, like the European Space Agency’s Euclid mission and the Vera C. Rubin Observatory in Chile, are preparing to share their findings.
Kris Pardo, a cosmologist at the University of Southern California uninvolved with the new research, emphasizes the need for multiple collaborations to achieve similar measurements at the gold standard to confirm dark energy’s weakening.
If dark energy remains constant, the universe might persist in its expansion indefinitely, growing increasingly distant and cold. Conversely, if dark energy diminishes over time—a possibility now on the table—the universe could eventually cease expanding and collapse on itself in a scenario known as the Big Crunch. While not the most uplifting conclusion, it offers some resolution, according to Mustapha Ishak-Boushaki, a study collaborator and cosmologist at the University of Texas at Dallas.
“There’s now a chance that everything has an endpoint,” Ishak-Boushaki remarked. “Is that a positive or negative outcome? That’s uncertain.”
