Can a Spinning Universe Solve the Hubble Tension?

By Taha KhanReviewed by Louis CastelFeb 27 2026

Modern cosmology rests on the idea that the universe is expanding at a measurable rate. That rate is described by the Hubble constant, which shows how fast galaxies are receding from one another as space stretches. However, over the past decade, measurements of this expansion rate have yielded conflicting results, a mismatch known as the Hubble tension. New models describing a slowly rotating or anisotropic universe might just help reconcile this discrepancy.

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Introduction

The Hubble tension refers to the disagreement between two methods of measuring the expansion of the universe. One method relies on observations of nearby galaxies and supernovae to determine the current expansion rate. The other infers the expansion rate indirectly from observations of the early universe, particularly the cosmic microwave background (CMB). These two approaches yield values that differ by more than their estimated uncertainties allow. The disagreement is not large in absolute terms, but it is statistically important and has proven difficult to reconcile.^{1, 2}

Researchers are exploring alternatives to the standard cosmological model to address this tension. Some of these ideas involve non-standard geometries of the universe, such as a small but non-zero global rotation. Although this concept of a spinning universe is unconventional, it emerges naturally from general relativity and has been revisited in light of current observational problems.^{1, 2}

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Theoretical Background: A Spinning Universe

In 1949, Kurt Gödel proposed a solution to Einstein’s field equations of general relativity that described a rotating cosmology, now known as the Gödel universe. In this model, the universe contains global rotation, which leads to unusual features such as closed timelike curves. Although Gödel’s solution is not considered a realistic description of our cosmos, it demonstrated that rotation is mathematically compatible with general relativity.³

Later work generalized these ideas through anisotropic cosmological models, like Bianchi cosmologies, which allow for directional dependence in expansion. Some of these models include global rotation or shear, meaning the universe could expand at slightly different rates along different axes.^{4, 5}

If the universe were rotating, even at an extremely slow rate, it would imply the existence of a preferred direction in space. This would manifest as cosmic vorticity, a measure of the large-scale twisting of spacetime. Over cosmological timescales, even a very small rotational component could influence the propagation of light and the interpretation of distance measurements.^{4, 5}

Hence, any realistic rotational model should involve extremely small angular velocities. Observations strongly constrain deviations from isotropy, so if rotation exists, it would be subtle. However, as cosmological inference depends on precise modeling, even small departures from perfect symmetry can affect the derived value of the Hubble constant.^{4, 5}

How Could Rotation Explain the Hubble Tension?

Some recent theoretical work has explored whether allowing the universe to have a small rotational component or directional anisotropy could change how measurements of cosmic expansion are interpreted. For example, in an anisotropic extension of ΛCDM explored using combined datasets including supernovae, baryon acoustic oscillations, and cosmic chronometers, it was found that introducing a tiny anisotropy parameter correlates with a slightly higher inferred Hubble constant than in the strictly isotropic case, suggesting a modification of inferred expansion rates could occur under such models.^{6, 7}

Cosmologists have proposed slowly rotating Gödel-inspired variants of the concordance model in which a weak global rotation affects the time evolution of the Hubble parameter. In one study published in Monthly Notices of the Royal Astronomical Society, incorporating a small angular velocity made it possible to extrapolate from a CMB-consistent early expansion to a present-day Hubble constant closer to locally measured values, though full consistency with all observations is work in progress.^{6, 7}

In these frameworks, anisotropy or rotation modifies how light propagates over cosmic distances and how redshifts from different epochs are interpreted. As CMB-based inferences and local distance ladder measurements sample different aspects of the universe’s expansion history, even subtle directional effects can, in principle, shift the inferred Hubble constant when data are interpreted under isotropic assumptions.^{6, 7}

Challenges and Observational Constraints

The primary challenge for spinning-universe models is in observational evidence supporting isotropy. The cosmic microwave background is uniform. Analyses of data from Planck have placed limits on large-scale anisotropy and vorticity. Any global rotation must be extremely small to remain consistent with these measurements.^{8, 9}

Studies of CMB anisotropies search for patterns that would indicate preferred directions or swirling signatures in the polarization field. So far, results have placed tight upper bounds on cosmic vorticity. These constraints restrict the degree of rotation compatible with the data.

Moreover, large-scale galaxy surveys also show statistical isotropy. The distribution of galaxies appears uniform when averaged over sufficiently large volumes. Although some anomalies have been reported, such as hemispherical asymmetries in the CMB, their statistical significance is still debated and does not provide clear evidence for global rotation.^{8, 9}

The standard ΛCDM model, despite the Hubble tension, explains a range of phenomena with a relatively small set of parameters. Therefore, any alternative should also match or exceed this explanatory power. Rotational models are viewed as exploratory rather than established.

Future Observations and Theoretical Directions

The coming decade of astronomy could provide the data needed to either confirm or completely reject these anisotropic models. For instance, the James Webb Space Telescope and the Euclid mission are mapping the distribution of galaxies with very high accuracy. If they find that galaxies tend to align or swirl on a scale of billions of light-years, it could revive the rotation theory. Similarly, the Square Kilometre Array (SKA) is a massive radio telescope that will be able to measure the rotation of millions of distant galaxies. Researchers can test if there is a large-scale cosmic flow that suggests a rotating background by studying the alignment of these spins.^{10, 11}

Some theorists are looking at Modified General Relativity or Scalar-Tensor theories, as these frameworks allow for more complex interactions between gravity and spacetime, where rotation might appear naturally as a solution to dark energy or the Hubble tension.¹²

Are Spinning Universe Models a Viable Solution?

The idea of a spinning universe is an attempt to solve a modern crisis by revisiting a classical concept. Currently, the skepticism is high about whether it is a viable solution. The uniformity of the CMB is a difficult barrier for any rotating model to overcome. However, the Hubble tension forces researchers to reevaluate the most basic assumptions.

The creative tension between observation and theory in modern cosmology is moving research forward, but any viable resolution of the Hubble tension will need to reconcile with the precise measurements that are consistent with isotropy and the standard cosmological model.

Need a refresher on the Hubble Tension?

References

1. Liu, M., Huang, Z., Luo, X., Miao, H., Singh, N. K., & Huang, L. (2020). Can non-standard recombination resolve the Hubble tension?. Science China Physics, Mechanics & Astronomy. https://doi.org/10.1007/s11433-019-1509-5
2. Riess, A. G., Yuan, W., Macri, L. M., Scolnic, D., Brout, D., Casertano, S., ... & Zheng, W. (2022). A comprehensive measurement of the local value of the Hubble constant with 1 km s− 1 Mpc− 1 uncertainty from the Hubble Space Telescope and the SH0ES team. The Astrophysical journal letters. https://doi.org/10.3847/2041-8213/ac5c5b
3. Momin, A. (2005). The Gödel Solution to the Einstein Field Equations. https://www.math.toronto.edu/colliand/426/Papers/A_Monin.pdf
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6. Yadav, V. (2023). Measuring Hubble constant in an anisotropic extension of ΛCDM model. Physics of the Dark Universe. https://doi.org/10.1016/j.dark.2023.101365
7. Szigeti, B. E., Szapudi, I., Barna, I. F., & Barnaföldi, G. G. (2025). Can rotation solve the Hubble Puzzle?. Monthly Notices of the Royal Astronomical Society. https://doi.org/10.1093/mnras/staf446
8. Saadeh, D., Feeney, S. M., Pontzen, A., Peiris, H. V., & McEwen, J. D. (2016). How isotropic is the universe?. Physical review letters. https://doi.org/10.1103/PhysRevLett.117.131302
9. Ade, P. A., Aghanim, N., Armitage-Caplan, C., Arnaud, M., Ashdown, M., Atrio-Barandela, F., ... & Noviello, F. (2014). Planck 2013 results. XXVI. Background geometry and topology of the universe. Astronomy & Astrophysics. https://doi.org/10.1051/0004-6361/201321546
10. Camarena, D., Marra, V., Sakr, Z., Nesseris, S., Da Silva, A., García-Bellido, J., ... & Tenti, M. (2023). Euclid: Testing the Copernican principle with next-generation surveys. Astronomy & Astrophysics. https://doi.org/10.1051/0004-6361/202244557
11. Toni, G., Gozaliasl, G., Maturi, M., Moscardini, L., Finoguenov, A., Castignani, G., ... & Yang, L. (2025). The COSMOS-Web deep galaxy group catalog up to z= 3.7. Astronomy & Astrophysics. https://doi.org/10.1051/0004-6361/202553759
12. Ji, P., & Shao, L. (2024). Scalar dark energy models and scalar–tensor gravity: theoretical explanations for the accelerated expansion of the present universe. Communications in Theoretical Physics. https://arxiv.org/pdf/2406.04954

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