When will the universe die?

DNVN - The universe has been expanding for 13.8 billion years, but according to some scientific theories, this process may not last forever. On the contrary, some scientists believe the universe is accelerating toward a catastrophic end.

Currently, the scientific community has a relatively clear understanding of the origin of the universe. According to the Big Bang theory, an extremely small and dense point of matter suddenly expanded 13.8 billion years ago, forming the universe as we know it today. Since then, the universe has been continuously expanding at an ever-increasing rate. However, precisely determining the future of the universe – or when and how it might end – remains a subject of debate among physicists.

"In physics, we can only trust theories when we have experimental data to verify them," Professor Nemanja Kaloper, a physicist at the University of California, Davis, shared in an email to Live Science. "However, in cosmology, that's extremely difficult because experiments are passive – we can't recreate the universe to test every scenario and improve the dataset at will."

So, when will the universe end? The answer depends on which theory is accepted. Two of the most prominent theories currently are the "Big Freeze" and the "Big Crunch".

The universe began with an explosion, but how will it end?

The Great Freeze Scenario

According to Professor Emeritus Henry Tye of Cornell University, the most likely scenario is the Big Freeze.

"This is exactly what's happening right now," Tye stated. "The expansion of the universe will continue to accelerate and last for 100 billion years, a trillion years, or possibly forever. There's no specific end point."

A modern cosmological model explains this expansion through the concept of "de-Sitter space"—a region of space possessing intrinsically positive energy, capable of pushing the universe further apart. This suggests the universe won't necessarily end, but it won't stand still either. True to its name, "Big Freeze," this scenario assumes that the energy in the universe will gradually thin to the point where all physical activity—from the burning of stars to the turbulence of black holes—will cease completely. Physicists call this the "thermal death" of the universe.

Scenario of the Big Shock

However, there remains the possibility that this de Sitter space will one day decay into negative energy – a factor that could reverse the expansion of the universe.

"That means the universe would continue to expand for a short time before reaching a maximum, then begin to contract," Professor Antonio Padilla of the University of Nottingham (UK) shared via email with Live Science. "Such a universe would end in a collapse."

This "Big Crunch" scenario would completely reverse the expansion of the Big Bang, thereby erasing all traces of the current universe. The worrying aspect, according to Professor Tye, is that this could have already happened in certain regions of space, but it would be very difficult to detect because all evidence would be completely wiped out.

Some recent theoretical models suggest that the Big Bang could occur as early as within the next 100 billion years. This conclusion is based on research into a type of dynamic dark matter called "quintessence." However, in a 2021 paper, Professor Padilla stated that the universe has at least a trillion years left before its end – and that's just a conservative estimate. He based this assessment on concepts from string theory – a theory that posits that fundamental particles are not points but rather tiny, one-dimensional strings.

The Big Break and Timeless Vision

However, even if the Big Bang were to occur, some scientists believe it would still be just one part of a larger cosmic cycle. This scenario is called the "Big Bounce," in which the universe is thought to have undergone and will continue to undergo a series of expansion – contraction – and expansion again. Accordingly, after collapsing into the initial conditions, the universe would explode again in a new Big Bang.

However, Padilla acknowledges that determining which theory is correct remains impossible.

"Predicting the distant future is always a challenge," he said. "In my opinion, empirical observations can only take us so far, given the complex nature of what we are studying."

The slow death of the universe

Even if none of the above theories are correct, the universe could still come to an end in a slower way. According to a study published in 2025 in the Journal of Cosmology and Astrophysics, all ordinary matter in the universe – including stars, galaxies, and even the remnants of dead stars like black holes – could slowly evaporate into nothingness due to a type of spontaneous radiation proposed by Stephen Hawking. The time it takes for all matter to completely evaporate is estimated to be 1 quinvigintillion years – equivalent to the number 1 after 78 zeros, or 10⁷⁸ years.

According to Professor Tye, there is currently no conclusive evidence to definitively state which theory is correct regarding the ultimate fate of the universe. Scientists are forced to constantly expand existing models and extrapolate to infinity. A better understanding of concepts such as dark energy and string theory is considered a crucial direction for more accurate predictions about the future of the universe.

Bao Ngoc (compiled)

Source: https://doanhnghiepvn.vn/cong-nghe/khi-nao-vu-tru-se-chet/20250524080939687