{"id":289387,"date":"2026-02-18T04:39:14","date_gmt":"2026-02-18T04:39:14","guid":{"rendered":"https:\/\/www.newsbeep.com\/nz\/289387\/"},"modified":"2026-02-18T04:39:14","modified_gmt":"2026-02-18T04:39:14","slug":"rather-than-expanding-forever-the-universe-may-be-doomed-to-crunch-in-20-billion-years","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/nz\/289387\/","title":{"rendered":"Rather Than Expanding Forever, The Universe May Be Doomed to “Crunch” in 20 Billion Years"},"content":{"rendered":"

\"Illustration<\/a>Illustration by ZME Science. <\/p>\n

We\u2019ve been told by science that the universe is expanding relentlessly, driven by a mysterious force called dark energy. Eventually, galaxies would drift so far apart that the night sky would go black, stars would burn out, and the universe would end in a \u201cBig Freeze\u201d \u2014 an eternal, heat-dead whimper.<\/p>\n

But a new study by theoretical physicists at Cornell University suggests we might need to rewrite that ending. Instead of fading away into infinite darkness, our universe could be destined for a dramatic, violent implosion known as the \u201cBig Crunch.\u201d<\/p>\n

According to calculations by Cornell physicist Henry Tye and his colleagues, the cosmos may be nearing the halfway point of a total lifespan of roughly 33 billion years. If their model holds up against scrutiny, we aren\u2019t drifting into a void. We are living in a universe that acts less like an endless balloon and \u201cmuch like a stretched rubber band snapping back.\u201d<\/p>\n

The Dark Energy Plot Twist<\/p>\n

To understand why the forecast has shifted from \u201cfreeze\u201d to \u201ccrunch,\u201d we have to look at the \u201ccosmological constant.\u201d Introduced by Albert Einstein a century ago, this constant (\u03bb) represents the energy density of empty space.<\/p>\n

\u201cFor the last 20 years, people believed that the cosmological constant is positive, and the universe will expand forever,\u201d says Tye, a professor emeritus at Cornell. A positive constant acts like a foot permanently stuck on the gas pedal, pushing the universe apart faster and faster.<\/p>\n

However, recent massive astronomical surveys \u2014 specifically the Dark Energy Survey (DES) in Chile and the Dark Energy Spectroscopic Instrument (DESI) in Arizona \u2014 have thrown a wrench in the gears. Their data, which maps millions of galaxies to measure cosmic history, suggests that dark energy isn\u2019t as steady as we thought. It seems to be evolving.<\/p>\n

\u201cThe new data seem to indicate that the cosmological constant is negative, and that the universe will end in a big crunch,\u201d Tye says.<\/p>\n

\"Graphic<\/a>Graphic by ZME Science based on data from Tye et al, Journal of Cosmology and Astroparticle Physics, 2025.<\/p>\n

In this scenario, the universe is currently expanding because of a temporary boost from other forces, but the underlying negative pressure of the cosmos is waiting in the wings. Eventually, it will hit the brakes. \u201cThis big crunch defines the end of the universe,\u201d Tye writes in the study published in the Journal of Cosmology and Astroparticle Physics<\/a>.<\/p>\n

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The Elusive Axion<\/p>\n

But if the cosmological constant is negative \u2014 which naturally pulls things together \u2014 why is the universe currently flying apart? Tye and his co-authors, Hoang Nhan Luu and Yu-Cheng Qiu, propose a culprit: an ultralight \u201caxion\u201d.<\/p>\n

Axions<\/a> are hypothetical particles (meaning they\u2019re not yet proven to exist) that are notoriously shy. They \u201conly interact with normal matter via gravity, making them very difficult to detect in a lab.\u201d In Tye\u2019s model, an incredibly light axion field permeates the universe.<\/p>\n

\u201cIt\u2019s simplest to assume that dark energy comes entirely from the cosmological constant,\u201d Tye says, but the data from DES and DESI imply a more complex reality.<\/p>\n

Here is how the physics plays out: Early in the universe\u2019s history, this axion field mimicked a positive cosmological constant, driving the expansion we see today. But unlike a true constant, the axion field is rolling down a hill of potential energy. As it rolls, its pushing power diminishes.<\/p>\n

Eventually, the axion\u2019s influence will fade. When it does, the true nature of the cosmological constant \u2014 the negative \u03bb \u2014 will be revealed. The expansion will lose its steam, and gravity will take the wheel.<\/p>\n

A Universe with an Expiry Date<\/p>\n

The team\u2019s model allows them to put a tentative expiration date on existence. The universe is currently 13.8 billion years old. Tye\u2019s calculations estimate a total lifespan of 33.3 billion years.<\/p>\n

That means we have roughly 20 billion years left. But the party doesn\u2019t end all at once.<\/p>\n

\u201cThe Universe\u2019s expansion is still accelerating now in our theory,\u201d explains co-author Hoang Nhan Luu. The shift will be gradual. <\/p>\n

\u201cThe Universe\u2019s expansion only slows down when the so-called \u2018crunching\u2019 phase starts, which may happen in the next 11 billion years, as a rough estimation, followed by a Big Crunch around eight billion years afterwards\u201d.<\/p>\n

So, for the next 11 billion years, the cosmos will continue to grow. Then, it will pause. Finally, it will begin to contract, shrinking for billions of years until all matter, energy, and spacetime collapse into a single point.<\/p>\n

Beyond the Event Horizon<\/p>\n

What happens after the collapse? This is where physics hits a wall. \u201cUnfortunately, our model can\u2019t give much prediction after the Universe collapses,\u201d Luu admits.<\/p>\n

The issue is a classic conflict in modern physics: the clash between general relativity (which governs gravity and the big stuff) and quantum mechanics (which rules the subatomic world). As the universe shrinks to a singularity, these two rulebooks have to merge, and we don\u2019t yet know how to read that language.<\/p>\n

Some physicists speculate about a \u201cBig Bounce\u201d \u2014 a scenario where the crunch immediately triggers a new Big Bang, creating a cyclical universe that breathes in and out for eternity. Tye is more cautious. \u201cHere, we predict the end of our Universe,\u201d he told BBC Science Focus<\/a>, \u201cbut precisely how it ends remains an open question. Just as one can predict a person\u2019s life expectancy without predicting the circumstances of the death\u201d.<\/p>\n

This prophecy of doom is far from settled science. It relies heavily on the data from DES and DESI, which show dark energy behaving strangely \u2014 specifically, that its equation of state, \u03c9, is not equal to -1. If future data snaps back to the standard model, the Big Crunch theory could vanish as quickly as it appeared.<\/p>\n

Fortunately, we won\u2019t have to wait billions of years to find out. <\/p>\n

More Data to Study the Universe<\/p>\n

A fleet of next-generation observatories is coming online to double-check the math.<\/p>\n

\u201cPeople have said before that if the cosmological constant is negative, then the universe will collapse eventually. That\u2019s not new,\u201d Tye notes. \u201cHowever, here the model tells you when the universe collapses and how it collapses\u201d.<\/p>\n

Upcoming data from the European Euclid space telescope, the Vera C. Rubin Observatory in Chile, and NASA\u2019s SPHEREx mission will test these predictions with unprecedented precision. If they confirm that dark energy is evolving, we may have to accept that our universe is mortal.<\/p>\n

\u201cFor any life, you want to know how life begins and how life ends \u2014 the end points,\u201d Tye says. \u201cFor our universe, it\u2019s also interesting to know, does it have a beginning? In the 1960s, we learned that it has a beginning. Then the next question is, \u2018Does it have an end?’\u201d.<\/p>\n

It seems the answer might be yes. And while 20 billion years is a long time, it\u2019s a good reminder that even the cosmos itself might not be too big to fail.<\/p>\n","protected":false},"excerpt":{"rendered":"Illustration by ZME Science. We\u2019ve been told by science that the universe is expanding relentlessly, driven by a…\n","protected":false},"author":2,"featured_media":289388,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[128510,1309,4016,2598,111,139,69,393,147,23272],"class_list":{"0":"post-289387","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-physics","8":"tag-axion","9":"tag-big-bang","10":"tag-big-crunch","11":"tag-dark-matter","12":"tag-new-zealand","13":"tag-newzealand","14":"tag-nz","15":"tag-physics","16":"tag-science","17":"tag-universe"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/289387","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=289387"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/289387\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/289388"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=289387"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=289387"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=289387"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}