“Apocalypse” how the universe stops expanding and begins to contract

New research published in the Proceedings of the National Academy of Sciences suggests that after nearly 13.8 billion years of continuous expansion, the universe could soon come to a standstill, then slowly begin to shrink.
In the new paper, 3 scientists attempt to model the nature of dark energy, a mysterious force that appears to be causing the universe to expand faster based on previous observations of cosmic expansion.

In the team's model, dark energy is not a constant force of nature, but rather an entity called substance, which can decay over time.

Researchers have found that although the expansion of the universe has accelerated for billions of years, the repulsive force of dark energy may be weakening.

According to their model, the acceleration of the universe could end within the next 65 million years, then within 100 million years, the universe could stop completely, and instead could enter an era of slow contraction that ends billions of years from now with the death or perhaps rebirth of time. and location.

As study co-author Paul Steinhardt, director of the Princeton Center for Theoretical Science at Princeton University in New Jersey, explained, all of this can happen quickly and remarkably.

Steinhardt told Live Science that going back in time 65 million years, that was when the Chicxulub asteroid hit Earth and wiped out the dinosaurs, on a cosmic scale, 65 million years remarkably short.

"Nothing in this theory is controversial or implausible," Gary Henshaw, a professor of physics and astronomy at the University of British Columbia who was not involved in the study, told Live Science.

However, because the model relies on previous observations of expansion alone, and because the current nature of dark energy in the universe is a mystery, it is currently impossible to test the predictions in this paper. For now, they can only remain theories.

Since the 1990s, scientists have realized that the expansion of the universe is accelerating, and now the distance between galaxies is expanding faster than it was billions of years ago.

Scientists have dubbed the mysterious source of this acceleration dark energy, an invisible entity that appears to work against gravity, pushing huge objects in the universe apart rather than clump together.

Although dark energy makes up nearly 70% of the universe's total energy, its properties remain a total mystery. The popular theory, advanced by Albert Einstein, is that dark energy is a cosmological constant.

However, a competing theory suggests that dark energy does not need to be constant to accommodate previous cosmic expansion observations.

Alternatively, the dark energy might be something called a core, which is a dynamic field that changes over time.

Unlike the cosmological constant, a substance can be repulsive or attractive, depending on the ratio of its kinetic energy and potential energy at a given time. For the past 14 billion years, the essence has been disgusting.