Microscopic wormholes might be responsible for the accelerated expansion of the universe, according to recent scientific research.

These tiny wormholes, which are continually forming from the vacuum of space due to subtle quantum effects, could provide new insights into quantum gravity—a theoretical framework that aims to unify all fundamental forces, often regarded as the Holy Grail of physics.

Astronomical observations consistently show that the universe is expanding at an ever-increasing rate. However, under Einstein's general theory of relativity, this accelerated expansion is impossible if the universe is composed solely of known particles and radiation.

To reconcile these observations, scientists have hypothesized the existence of a mysterious entity pervading space—dark energy. This enigmatic force interacts so weakly with matter that it remains undetectable by current ground-based or space-based experiments, leaving its nature and origin a profound mystery.

In a study published on April 5 in the journal Physical Review D, researchers proposed a bold new candidate for dark energy: subatomic-sized wormholes—tiny tunnels connecting distant points in space.

These wormholes, the researchers suggest, are continuously being born and destroyed in the vacuum due to quantum effects, similar to the way particles are generated near black hole event horizons, leading to Hawking radiation, or how electron-positron pairs emerge in strong electric fields—a phenomenon known as the Schwinger effect.

However, the formation of these wormholes differs from other quantum phenomena because it involves the complex and poorly understood realm of quantum gravity. This complexity has so far prevented the researchers from accurately determining the rate at which these wormholes form.

Despite this challenge, using a method called Euclidean quantum gravity, they estimated that if approximately 10 billion wormholes are spontaneously created per cubic centimeter every second, the energy produced would match the observed rate of the universe's expansion.

"Although our results were derived using Euclidean quantum gravity, it’s likely that our modification may apply to other quantum gravity theories as well," said study co-author Stylianos Tsilioukas, a doctoral student at the University of Thessaly and the National Observatory of Athens, in an email to Live Science.

Moreover, the team found that their model of dark energy aligns even better with observations than the widely accepted Standard Cosmological Model, which assumes dark energy has a constant energy density over time.

"According to our proposal, dark energy can change as time progresses," Tsilioukas explained. "This is a significant advantage, as recent observations suggest that the rate of the universe's expansion differs between the early universe and more recent times."

Despite the promise of this new model, its validity can only be confirmed through experimental data. Currently, the theory remains untested.

In the future, increasingly precise space-based experiments and observations should enable astronomers to measure the universe’s expansion rate and other manifestations of dark energy in greater detail, potentially allowing them to test this new model.

In the meantime, the researchers are focused on refining their theoretical analysis. "We are currently working on a model to calculate the rate of wormhole formation," Tsilioukas said. "The research looks promising, and we hope to publish our findings soon."

Sources:

Published 5 April 2024 in Physical Review D Journal; Dark energy from topology change induced by microscopic Gauss-Bonnet wormholes

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