Fresh analysis of dark energy observations indicates the universe could collapse in a big crunch after expanding for another 11 billion years. Cornell physicist Henry Tye's model, based on data from major surveys, predicts a total lifespan of about 33 billion years for the cosmos. This challenges long-held views of endless expansion.
The universe, currently aged 13.8 billion years and still expanding, faces a potential dramatic turnaround according to recent calculations. Henry Tye, the Horace White Professor of Physics Emeritus at Cornell University, has updated a model centered on the cosmological constant—a concept introduced by Albert Einstein over a century ago. His findings, detailed in the paper "The Lifespan of our Universe" published in the Journal of Cosmology and Astroparticle Physics, suggest the universe is approaching the midpoint of its existence, with a maximum expansion in roughly 11 billion years followed by contraction leading to a collapse in about 20 billion years.
Tye's conclusions draw from 2025 data releases by the Dark Energy Survey (DES) in Chile and the Dark Energy Spectroscopic Instrument (DESI) in Arizona. These observatories, which probe dark energy comprising 68% of the universe's mass and energy, show results that align closely despite their hemispheric separation. The data imply the cosmological constant may be negative, deviating from the positive value assumed for two decades that would sustain perpetual expansion.
"For the last 20 years, people believed that the cosmological constant is positive, and the universe will expand forever," Tye stated. "The new data seem to indicate that the cosmological constant is negative, and that the universe will end in a big crunch."
To reconcile the observations, Tye and co-authors Hoang Nhan Luu and Yu-Cheng Qiu propose a hypothetical low-mass particle that initially mimicked a constant but evolved over time, shifting the constant negative. "This big crunch defines the end of the universe," Tye wrote.
While the idea of a negative constant leading to collapse is not novel, Tye's model specifies the timeline. Further observations from projects like the Zwicky Transient Facility, the European Euclid space telescope, NASA's SPHEREx mission, and the Vera C. Rubin Observatory will test these predictions. Tye emphasizes the value in defining cosmic endpoints: "For our universe, it's also interesting to know, does it have a beginning? ... Does it have an end?"