Scientists have discovered that rapid rotation may significantly slow down the instability of theoretical wormholes, potentially allowing these mysterious cosmic structures to remain open for much longer than previously expected.
In a new study, researchers Shirokov and Nachevsky have investigated the stability of rotating Ellis–Bronnikov wormholes using advanced computer simulations. Their findings suggest that rotation can dramatically change how wormholes behave, with some rapidly spinning models showing no signs of collapse or expansion during the simulated period.
The research provides new insights into one of the biggest challenges in theoretical physics: understanding whether a traversable wormhole could remain stable over time.
What Are Ellis–Bronnikov Wormholes?
Wormholes are hypothetical structures in spacetime that could connect two distant regions of the universe through a tunnel-like passage. Although they are allowed by certain solutions of Einstein's general theory of relativity, no wormhole has ever been observed.
The Ellis–Bronnikov wormhole is a theoretical model supported by an unusual type of mathematical field known as a phantom scalar field. This field has properties that differ from ordinary matter and can theoretically provide the negative energy required to hold a wormhole's throat open.
However, these wormholes have a major problem: instability.
Previous research has shown that a static Ellis–Bronnikov wormhole can develop two different outcomes when disturbed. Its central throat can collapse, potentially forming a black hole, or expand uncontrollably.
This instability makes it difficult to imagine such a wormhole remaining open long enough to be useful as a stable passage through spacetime.
Can Rotation Make Wormholes More Stable?
Scientists have long considered rotation as a possible solution to the wormhole stability problem.
The basic idea is that spinning objects behave differently from stationary ones because rotation changes their gravitational and spacetime geometry. Researchers wanted to investigate whether this effect could prevent a wormhole from collapsing.
Earlier studies examined rotating Ellis–Bronnikov wormholes using mathematical approximations. These calculations suggested that increasing rotation could weaken the original instability.
However, those studies could not fully determine what would happen at higher rotation speeds.
Some theoretical predictions even suggested that two unstable modes might merge at around 30% of the maximum possible angular momentum, potentially causing the instability to disappear.
But this possibility had not been confirmed through fully nonlinear simulations.
To investigate the question, Shirokov and Nachevsky developed advanced numerical methods to construct and evolve rotating wormhole models.
Advanced Simulations Reveal Surprising Results
The researchers constructed two families of rotating Ellis–Bronnikov wormholes, including symmetric models and asymmetric drainhole configurations.
Their numerical solver successfully generated rotating solutions with equatorial speeds reaching approximately 99% of the speed of light.
They also tested their calculations against previously published results to ensure accuracy. During this process, they discovered and corrected an inconsistency in a previously published mathematical field equation.
After validating their models, the researchers transferred the solutions onto an adaptive mesh refinement (AMR) simulation grid. This technique allows computers to concentrate computational resources in regions where greater numerical accuracy is needed.
They then performed nonlinear 3+1 dimensional simulations of the rotating drainhole wormholes at nine different rotation rates.
Unlike earlier mathematical approximations, these simulations allowed the researchers to investigate how the wormholes evolved under the full nonlinear equations of gravity.
Rotation Slows Down Wormhole Instability
One of the most important findings was that increasing rotation significantly slowed the collapse of the wormhole throat.
In the nonrotating model, the throat collapsed on a timescale of approximately 5.4 units.
When the wormhole reached 24% of the extremal angular momentum, its collapse time increased to approximately 13.3 units.
This indicates that rotation can make the instability considerably slower.
The researchers also examined how the collapse rate changed with angular momentum. Their calculations suggested that the collapse rate could approach zero at approximately 32% of the extremal angular momentum.
Interestingly, this result was close to the earlier second-order perturbation prediction of approximately 33%.
However, the most surprising discovery appeared near 30% of the maximum angular momentum.
A Wormhole Throat Changes Its Behaviour
Instead of simply becoming stable, the wormhole's behaviour changed near 30% of the extremal angular momentum.
The researchers found that the unperturbed throat began expanding rather than collapsing.
This was particularly interesting because earlier theoretical calculations had suggested that the instability might disappear when two unstable modes merged.
The new simulations revealed a different possibility: the instability could change its outcome from collapse to expansion.
In other words, rotation does not necessarily eliminate the instability. It can fundamentally change how the wormhole evolves.
Rapidly Spinning Wormholes Show No Instability
Perhaps the most significant result came from the rapidly rotating models.
From approximately 58% of the extremal angular momentum upward, the researchers found no evidence of throat growth within the simulated time periods.
At the fastest tested rotation rates, the wormhole remained stable against the observed axisymmetric disturbances throughout the simulations.
One particularly interesting model, rotating at approximately 81% of the extremal angular momentum, showed no detectable growth up to simulation time 150.
This corresponds to roughly 28 e-folding times of the unstable mode found in the static wormhole.
Importantly, the researchers repeated this simulation at three different numerical resolutions and obtained consistent results.
These findings provide strong evidence that sufficiently rapid rotation can suppress the observed axisymmetric instability over substantial periods.
However, they do not prove that rotating wormholes are completely stable under every possible disturbance.
Rotating Wormholes Could Produce Gravitational Waves
The study also revealed another fascinating feature.
When rotating wormholes underwent throat collapse, they produced bursts of gravitational waves.
These waves were primarily associated with an axisymmetric quadrupolar mode, commonly described as the (2,0) gravitational-wave mode.
Interestingly, the energy released through these gravitational waves increased with the wormhole's rotation speed.
This suggests that rotating wormholes could have distinctive gravitational-wave signatures if such theoretical objects existed in nature.
Gravitational waves are ripples in spacetime produced by accelerating masses. They have already been detected from events involving black holes and neutron stars.
Although the wormholes studied here are theoretical, their predicted gravitational-wave behaviour could help researchers understand how different exotic spacetime configurations might appear in future observations.
Important Limitations of the Research
Despite the promising results, the researchers emphasize that their findings should not be interpreted as proof that rotating wormholes are permanently stable.
Their simulations covered a finite period, ending at or before time 150. A much slower instability could potentially appear later.
Furthermore, the simulations began with axisymmetric conditions. This means they cannot rule out non-axisymmetric instabilities that might affect rapidly rotating wormholes.
The researchers also found that second-order perturbative initial data could trigger instability through their own numerical errors, making them unsuitable for reliable nonlinear stability investigations.
Additionally, only the asymmetric drainhole family was evolved in the simulations. The symmetric family was used to validate the numerical solver.
A New Direction in Wormhole Research
The study by Shirokov and Nachevsky represents an important step toward understanding rotating wormholes and their behaviour under Einstein's equations.
Its central finding is that rotation does much more than simply slow down wormhole collapse. At different rotation rates, it can change the evolution of the throat, potentially replacing collapse with expansion or suppressing detectable instability altogether.
Although stable, traversable wormholes remain theoretical and have never been observed, these results offer scientists a better understanding of how rotation influences exotic spacetime structures.
Future research will need to investigate longer simulation periods, non-axisymmetric disturbances and other wormhole configurations to determine whether rapid rotation can genuinely produce long-lasting stability.
For now, the findings raise an intriguing possibility: could extreme rotation be one of the keys to keeping a theoretical wormhole open?
Reference: Nikita M. Shirokov, Ilya Nachevsky, "Rotation slows the instability of Ellis-Bronnikov wormholes", Arxiv, 2026. https://arxiv.org/abs/2610.29941
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