Universe expected to decay in 10⁷⁸ years, much sooner than previously thought
A new study published in the Journal of Cosmology and Astroparticle Physics by three researchers at Radboud University in the Netherlands has dramatically revised our estimate of when the last objects in the universe will cease to exist. The previous estimate was not just slightly wrong.
Science Aim — Science Universe expected to decay in 10⁷⁸ years, much sooner than previously thought Last updated: April 12, 2026 8:20 am Brain Articles Share Artistic impression of a neutron star that is 'evaporating' slowly via Hawking-like radiation. Credit: Daniëlle Futselaar/artsource. nl SHARE A new study published in the Journal of Cosmology and Astroparticle Physics by three researchers at Radboud University in the Netherlands has dramatically revised our estimate of when the last objects in the universe will cease to exist.
That is a 1 followed by 78 zeros. It sounds incomprehensibly long, and it is. But it is also vastly shorter than the previous estimate of 10¹¹⁰⁰ years , which is a 1 followed by 1,100 zeros.
To put that difference in perspective: the gap between those two numbers is so enormous that no analogy from everyday life can adequately capture it. The previous estimate was not just slightly wrong. It was wrong by a margin that makes the difference between a second and the current age of the universe look trivial by comparison.
And the reason for the revision is a process called Hawking-like radiation , which turns out to apply not just to black holes, as was previously assumed, but to almost everything in existence. What Is Hawking Radiation, and Why Does It Matter? In 1975, physicist Stephen Hawking proposed something that contradicted what many physicists believed about black holes.
He argued that black holes are not completely black. They leak. Very, very slowly.
An illustration showing what generates Hawking radiation. Credit: Getty Images The popular explanation, the one Hawking himself used in talks and books, involves pairs of virtual particles that pop into existence near the edge of a black hole. At the edge of a black hole, two temporary particles can form, and before they merge, one particle is sucked into the black hole and the other particle escapes, producing what is called Hawking radiation.
The particle that escapes carries energy with it. That energy has to come from somewhere, and the somewhere is the black hole itself. Over extraordinarily long timescales, the black hole loses mass and eventually evaporates entirely.
This contradicts Albert Einstein’s theory of relativity, which says that black holes can only grow. It is worth noting that physicists now understand the virtual particle explanation to be a useful simplification rather than a fully accurate picture of what is happening. The true mechanism is more subtle , involving the way that curved spacetime and quantum uncertainty interact to produce radiation from any region where gravity bends space strongly enough.
But the outcome is the same: black holes slowly radiate away their mass, and given enough time, they disappear. The 2023 Discovery That Changed Everything The new study builds directly on a 2023 paper by the same trio : black hole expert Heino Falcke , quantum physicist Michael Wondrak, and mathematician Walter van Suijlekom. In that earlier paper, they made a significant and surprising claim.
Hawking radiation is not unique to black holes. Any object with a gravitational field can, in principle, evaporate via the same process. They showed that not only black holes, but also other objects such as neutron stars, can evaporate via a process akin to Hawking radiation.
That finding raised an immediate follow-up question from the scientific community and from curious members of the public alike: if everything evaporates, how long does the process actually take? After that publication, the researchers received many questions from inside and outside the scientific community about how long the process would take. They have now answered this question in the new article.
How the Study Was Conducted The team used mathematical calculations drawn from three different fields: astrophysics, quantum physics, and pure mathematics. They worked through ten different types of objects, calculating from first principles how long each would take to evaporate via Hawking-like radiation in an ideal environment with no other influences. The calculations further showed that the evaporation time of an object depends only on its density.
That is a deceptively elegant result. It means that the clock for how long an object lasts has nothing to do with its size, its composition, or its history. Only its density determines its fate.
Findings From the Study The results produced a table of cosmic lifetimes that is simultaneously mind-bending and strangely clarifying. The most significant finding concerns white dwarf stars , which the researchers identify as the last survivors in the universe. White dwarf stars dissolve in about 10⁷⁸ years.
Previous studies, which did not take this effect into account, put the lifetime of white dwarfs at 10¹¹⁰⁰ years. White dwarfs are the dense, cooling remnants left behind when stars like our Sun have exhausted their nuclear fuel. A Hubble Space Telescope colour image of a small portion of the cluster only 0.
63 light-years across reveals eight white dwarf stars among the cluster’s much brighter population. White dwarf stars, the dense cooling remnants of stars like our Sun, are predicted to be the last stellar objects to evaporate via Hawking-like radiation, dissolving after about 10⁷⁸ years. About 97% of Milky Way stars will end up as white dwarfs.
They are not actively burning anything. They are simply cooling down, extremely slowly, over immense stretches of time. Approximately 97 percent of the stars in the Milky Way will eventually become white dwarfs.
They are, in essence, the embers of the universe. And according to this new research, those embers will finally go cold and vanish at around 10⁷⁸ years. The Counterintuitive Finding About Black Holes One of the most striking results in the paper concerns the relative lifetimes of neutron stars and black holes.
Common sense would suggest that black holes, with their extraordinarily powerful gravitational fields, should evaporate faster via Hawking radiation. A stronger gravitational field should produce more radiation. More radiation should mean faster decay.
But the calculations produced a surprising result. To the researchers’ surprise, neutron stars and stellar black holes take the same amount of time to decay: 10⁶⁷ years. This was unexpected because black holes have a stronger gravitational field, which should cause them to evaporate faster.
The reason turns out to come down to geometry. Black holes have no surface. They reabsorb some of their own radiation, which inhibits the process, said co-author and postdoctoral researcher Michael Wondrak.
A neutron star has a surface. Radiation that leaves a neutron star is gone, contributing to the evaporation process without being recaptured. A black hole, by contrast, has an event horizon, and some of the radiation it produces loops back inward and is reabsorbed.
The two effects cancel each other out, and the two objects end up with essentially the same lifespan. This is not a trivial result. It tells us something fundamental about the relationship between the geometry of objects and the rate at which they decay.
What Makes This Genuinely Surprising Most people, when they think about the death of the universe, picture it as something that happens to the grand structures: the galaxies, the clusters, the supermassive black holes at the heart of everything. The intuition is that ordinary matter, the atoms, the rocks, the planets, will long outlast the exotic celestial objects. The new research overturns that intuition in an interesting way.
Because the researchers were at it anyway, they also calculated how long it takes for the Moon and a human to evaporate via Hawking-like radiation. That is 10⁹⁰ years. That is longer than the 10⁷⁸ years it takes a white dwarf to dissolve.
So in the Hawking radiation picture, the Moon and a hypothetical human body would outlast the last stars in the universe. Of course, the researchers note with characteristic understatement that there are other processes that may cause humans and the moon to disappear faster than calculated. Practically speaking, neither the Moon nor any human will be around in anything close to 10⁷⁸ years.
The Sun will swell into a red giant in about five billion years, consuming the inner solar system. But taken purely as a calculation of Hawking-like evaporation in ideal conditions, the math tells us that less dense objects take longer to decay. Since the Moon and a human body are far less dense than a white dwarf, they would take longer to evaporate via this mechanism.
It is a result that is genuinely funny if you think about it too long How This Applies to Our Understanding of the Universe The study is clear that it addresses only Hawking-like radiation in isolation. The actual end of the universe involves many other processes, some of which are better understood and some of which remain deeply mysterious. The long-term fate of the cosmos depends on the nature of dark energy, the behaviour of protons over cosmological timescales, and phenomena that current physics cannot fully predict.
But what this research does is establish something important: the upper limit on how long stellar remnants can last . Even if every other physical process were somehow paused, Hawking-like radiation alone would guarantee the universe cannot persist beyond approximately 10⁷⁸ years. That is why the paper is titled precisely as it is: an upper limit to the lifetime of stellar remnants.
Professor Walter van Suijlekom, professor of mathematics at Radboud University, adds that the research is an exciting collaboration of different disciplines and that combining astrophysics, quantum physics and mathematics leads to new insights. “By asking these kinds of questions and looking at extreme cases, we want to better understand the theory, and perhaps one day, we will unravel the mystery of Hawking radiation. ” That last point is the deeper motivation behind the work.
Hawking radiation has never been directly observed. It is almost certainly undetectable with any instrument that currently exists or that could be built in the foreseeable future, because for stellar-mass black holes the radiation is far too faint to measure against the cosmic background. Calculating its effects across the full range of objects in the universe, and identifying unexpected results like the equivalence of black hole and neutron star lifetimes, is one of the few ways physicists can probe and test the theory indirectly.
Holding the Numbers in Mind There is a particular kind of vertigo that comes from trying to comprehend numbers like 10⁷⁸. The universe is currently about 13. 8 billion years old, which is roughly 10¹⁰ years.
The new estimate for the end of the universe is 10⁷⁸ years, which means the time remaining is longer than the current age of the universe by a factor of about 10⁶⁸. That is a 1 followed by 68 zeros. Every event that has ever occurred in the history of the cosmos, from the Big Bang to the formation of the first stars, from the emergence of life on Earth to this very moment, has taken place within the first 10⁻⁶⁸ of the universe’s total lifespan under the new estimate.
We are, cosmically speaking, in the very earliest fraction of a fraction of a second after the opening. “So the ultimate end of the universe comes much sooner than expected, but fortunately it still takes a very long time,” said lead author Heino Falcke . That statement is delivered with the calm of a scientist who has spent a long time sitting with these numbers.
It is also, in its quiet way, an unexpectedly reassuring thing to hear. The universe will end. But not for a very long time.
And somewhere in the mathematics of how it will happen, in the way that curved space leaks energy and density determines fate, there is a kind of deep order to the process that scientists like Falcke, Wondrak, and Van Suijlekom are working, patiently and across disciplines, to understand. More Findings from the Study The paper itself establishes several additional findings that are worth unpacking carefully, because they reveal a picture of the universe’s fate that is considerably richer and stranger than the headline number alone conveys. One of the most technically striking results in the study concerns the precise mathematical relationship governing how long objects last.
The researchers found that the evaporation timescale, which they denote as tau, scales with the average mass density of an object according to the relationship tau proportional to density to the power of negative three halves. In plain terms, this means that denser objects evaporate faster, and less dense objects last longer , regardless of how large or massive they are. This is a genuinely counterintuitive result, because our everyday instinct is that heavier, denser things are more durable.
In the language of Hawking-like radiation, the opposite is true. A teaspoon of neutron star material, the densest ordinary matter in the universe at roughly 300 million tonnes per teaspoon, will vanish far sooner than a region of diffuse interstellar gas spread across light-years of space. The paper provides a cascade of specific lifetimes that make this density dependence vivid and almost philosophically disorienting.
Neutron stars, the collapsed remnants of massive stars that have exploded as supernovae, have densities in the range of 3. 3 times 10¹⁴ grams per cubic centimetre. Their evaporation timescale under the new calculation is approximately 10⁶⁸ years.
White dwarfs, which are less dense because they are the remnants of lighter stars like our Sun, evaporate in approximately 10⁷⁸ years. The Moon, with a density of about 3. 4 grams per cubic centimetre, a density comparable to granite, would take approximately 3 times 10⁸⁹ years to evaporate.
An object with the density of water would last approximately 10⁹⁰ years. The Local Interstellar Cloud, the diffuse bubble of gas and plasma in which our solar system currently sits, with a density of roughly 5 times 10⁻²⁵ grams per cubic centimetre, would persist for approximately 10¹²⁷ years. A supercluster dark matter halo, representing the largest and most diffuse gravitationally bound structures in the universe, would survive for approximately 10¹³⁵ years.
These numbers establish a clear and elegant ordering.