Two papers. Two mechanisms. Two wildly different timescales. The headlines this week treated them as one story — “the universe will end much sooner than expected” — without distinguishing which study said what, which is peer-reviewed, or why the most alarming number comes from a model that was considered a dead end for decades.
Here is what each study actually found, and what it would take to believe them.
- Radboud University (peer-reviewed)
- Universe's last structures evaporate in ~10^78 years via Hawking-like radiation. Previous estimate: 10^1100 years. Both timescales are incomprehensibly large.
- Cornell / aDE model (preprint)
- Universe collapses in 33.3 billion years — about 2.4× its current age — via Big Crunch. Based on fitting one speculative dark energy model to ambiguous data.
- What they share
- The word "sooner." That is approximately where the overlap ends.
Study one: Hawking radiation kills everything, eventually
The Radboud University paper, published in the Journal of Cosmology and Astroparticle Physics in May 2025, is the solid one. Physicists Heino Falcke, Michael Wondrak, and Walter van Suijlekom extended Hawking’s radiation framework — originally developed for black holes — to other dense objects like white dwarfs and neutron stars.
The principle: at the boundary of any sufficiently massive, curved object, quantum fluctuations spontaneously produce particle-antiparticle pairs. One particle escapes; the other is absorbed. The object loses mass. Very, very slowly — but over enough time, completely.
For a stellar-mass black hole, this takes roughly 10^67 years. For a white dwarf — which is denser and more stable than a black hole — it takes about 10^78 years. The previous estimate, which didn’t account for this mechanism in non-black-hole objects, was 10^1100 years.
This is a real result. It extends an established physical framework in a non-obvious direction, is peer-reviewed, and gives us a more complete picture of how the universe eventually winds down under known physics. The timescale remains so vast that it is operationally indistinguishable from “never” for any practical purpose.
Study two: the Big Crunch in 33 billion years
This is the alarming number, and it requires more skepticism.
Henry Tye at Cornell and collaborators published a preprint — not yet peer-reviewed — applying an “axion dark energy” (aDE) model to data from the Dark Energy Spectroscopic Instrument (DESI) and the Dark Energy Survey. The model proposes that dark energy is not a cosmological constant — a fixed, unchanging property of space — but instead a combination of that constant and an ultra-light quantum field called an axion. In this model, the interplay between those two components causes dark energy to weaken and eventually reverse, pulling the universe back inward toward a Big Crunch.
Their best-fit parameters, applied to current observational data, give a universe lifespan of 33.3 billion years. The current universe is 13.8 billion years old. That leaves approximately 19.5 billion years.
The observational hook is real: DESI data released in 2024 showed mild but statistically significant tension with a fixed cosmological constant. Something in the dark energy measurements is not behaving the way a simple constant would predict. Multiple models have been proposed to explain this — the axion dark energy model is one of them.
Why the Big Crunch was off the table
After the 1998 discovery that cosmic expansion is accelerating — which earned the 2011 Nobel Prize — the Big Crunch largely disappeared from serious cosmological discussion. Accelerating expansion implies dark energy is winning, permanently. A reversal would require dark energy to not just stop, but to flip sign — to become attractive rather than repulsive.
The competing end-state scenario that gained traction instead was the Big Rip: dark energy accelerates so strongly that it eventually overcomes gravity at increasingly small scales, tearing apart galaxies, then solar systems, then atoms. That’s a different kind of “much sooner than expected” — and it also depends on which dark energy model you use.
The DESI data reopened both possibilities. The debate between Big Rip, Big Crunch, and continued indefinite expansion is now genuinely unsettled in a way it wasn’t five years ago. That is the actual headline. The specific number — 33 billion years — comes from one model fit to ambiguous data and should not be treated as a measurement.
What to take from this
The Hawking radiation result is interesting physics regardless of the timescale. It tells us that compact objects we thought were permanent will eventually evaporate — and it provides a mechanism for the long-term fate of matter that was previously unaccounted for.
The axion dark energy result is a model, not a finding. It is worth watching. If DESI’s dark energy anomaly deepens as more data comes in, and if independent analyses favor models that predict a reversal, then the Big Crunch scenario will become more credible. Right now it is an intriguing fit to noisy data from a team with a particular theoretical framework.
The universe is not about to end on any timescale relevant to any concern you might reasonably have. The Hawking radiation study is peer-reviewed and meaningful: it extends established physics to show that the universe's last structures will evaporate in 10^78 years rather than 10^1100 — a revision that matters to physics, not to planning.
The 33-billion-year Big Crunch figure is a preprint artifact of one speculative model applied to ambiguous data. The underlying DESI anomaly is real and worth following — it may be the first observational crack in our understanding of dark energy. But the specific collapse date is not something the data actually supports. When you see "universe to end sooner than expected," ask which study, which mechanism, and whether it's been peer-reviewed. This week, the answer splits cleanly in two.