Recent scientific calculations suggest that the Universe may face a dramatic end in approximately 33.3 billion years. This prediction arises from new insights into dark energy, which is believed to be evolving. According to physicists Hoang Nhan Luu of the Donostia International Physics Center in Spain, Yu-Cheng Qiu of Shanghai Jiao Tong University in China, and corresponding author Henry Tye of Cornell University in the United States, the Universe has already existed for about 13.8 billion years, indicating that we have nearly 20 billion years remaining.
The research indicates that for another 11 billion years, the Universe will continue to expand. Eventually, this expansion will halt and reverse, leading to a scenario known as the Big Crunch. Tye emphasizes that the new findings challenge the long-held belief that the Universe will expand indefinitely, which has been the prevailing theory for the past two decades.
“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.”
The cosmological constant, denoted as λ, was introduced by Albert Einstein in his theory of general relativity. When λ is positive, it exerts an outward force, contributing to the Universe’s expansion. A negative λ, on the other hand, acts as an inward pull that can eventually reverse expansion. Current observations suggest that dark energy may indeed be changing over time, leading to this new model.
In this analysis, Tye and his colleagues propose a scenario where a small negative λ combines with an ultralight axion field. Axions are theoretical particles that could provide a smooth field throughout space and have been suggested as potential solutions to various issues in particle physics. In the new model, the axion initially provides a gentle outward push that gradually diminishes over time.
At present, the influence of the axion continues to push the Universe outward, resulting in ongoing acceleration as gravitational forces weaken. However, after about 11 billion years, the axion’s effect will weaken sufficiently for the negative λ to dominate, bringing the Universe’s expansion to a standstill. The maximum size of the Universe at that point is estimated to be about 1.7 times its current size.
The subsequent contraction will happen rapidly, culminating in the Big Crunch within approximately 8 billion years. Tye likens this process to riding a bicycle uphill with a tailwind. As the tailwind eases, the ascent slows, eventually coming to a stop before descending rapidly.
The Big Crunch represents a reversal of the Big Bang, where all matter in the Universe would collapse into an infinitely dense singularity. While this model presents a fascinating perspective on the Universe’s fate, Tye stresses that it remains one of many possibilities and not a definitive prediction.
Further data will be essential to validate whether dark energy is evolving as suggested. The nature of dark energy itself remains elusive, and it is uncertain whether it is composed of axions or entirely different particles.
In discussing the significance of understanding the Universe’s lifespan, Tye remarked, “For any life, you want to know how life begins and how life ends – the end points.” He added that while the early universe’s beginning has been established, the question of its end has been less clear.
The findings from this research have been published in the Journal of Cosmology and Astroparticle Physics, providing a potential answer to one of the most profound questions in cosmology.
