Universe May End in 'Big Crunch,' Dark Energy Data Suggests

Cornell physicist calculates cosmos could collapse in 20 billion years after reaching maximum size.

Published on Feb. 16, 2026

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A Cornell physicist has calculated that the universe may be nearing the halfway point of a total lifespan of about 33 billion years. Using newly released data from major dark energy observatories, he concludes that the cosmos will continue expanding for roughly another 11 billion years before reaching its largest size. After that, it would begin to shrink, eventually collapsing back into a single point, much like a stretched rubber band snapping back.

Why it matters

This updated model challenges the long-held belief that the universe will expand forever. If confirmed, it would provide new insights into the beginning and end of our cosmic history, with major implications for our understanding of dark energy and the ultimate fate of the universe.

The details

Henry Tye, the Horace White Professor of Physics Emeritus at Cornell, arrived at this conclusion by updating a long-standing model built around the "cosmological constant" concept first introduced by Albert Einstein. The new data from the Dark Energy Survey (DES) in Chile and the Dark Energy Spectroscopic Instrument (DESI) in Arizona suggest the cosmological constant may actually be negative, leading to an eventual "big crunch" rather than endless expansion.

  • The universe is currently 13.8 billion years old.
  • The universe will continue expanding for roughly another 11 billion years before reaching its maximum size.
  • The universe will then begin to shrink and collapse in about 20 billion years from now.

The players

Henry Tye

The Horace White Professor of Physics Emeritus in the College of Arts and Sciences at Cornell University, and the corresponding author of the study.

Dark Energy Survey (DES)

A major dark-energy observatory located in Chile that has provided key data for Tye's updated model.

Dark Energy Spectroscopic Instrument (DESI)

A dark-energy observatory located in Arizona that has also contributed important data for Tye's calculations.

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What they’re saying

“For the last 20 years, people believed that the cosmological constant is positive, and the universe will expand forever. The new data seem to indicate that the cosmological constant is negative, and that the universe will end in a big crunch.”

— Henry Tye, Horace White Professor of Physics Emeritus (Journal of Cosmology and Astroparticle Physics)

“This big crunch defines the end of the universe.”

— Henry Tye, Horace White Professor of Physics Emeritus (Journal of Cosmology and Astroparticle Physics)

What’s next

Hundreds of researchers are studying millions of galaxies and measuring the distances between them to refine estimates of dark energy. DESI will continue collecting observations for another year, and additional projects like the Zwicky Transient Facility, the European Euclid space telescope, NASA's SPHEREx mission, and the Vera C. Rubin Observatory are already contributing or preparing to begin observations.

The takeaway

This updated model challenges the long-held belief that the universe will expand forever, providing new insights into the beginning and end of our cosmic history. If confirmed, it would have major implications for our understanding of dark energy and the ultimate fate of the universe.