[Image Credit: NASA]
One might assume that galaxies in our universe would have no favored spin, rotating randomly either clockwise or counterclockwise. Yet a recent discovery from the James Webb Space Telescope (JWST) challenges this fundamental notion. JWST’s Advanced Deep Extragalactic Survey (JADES) analyzed 263 galaxies from the early universe and revealed a significant asymmetry: roughly 66% spin clockwise, while only about 33% rotate counterclockwise.
This cosmic imbalance has resparked a scientific debate: does it reveal a universe born from a spinning black hole, or simply reflect how we observe galaxies from Earth?
Lior Shamir, associate professor of computer science at Kansas State University, recently published the findings in the Monthly Notices of the Royal Astronomical Society.
By applying a symmetric, computer-aided algorithm to the JADES data, Shamir uncovered that in a region of the sky near the Southern Galactic Pole, 158 galaxies were rotating clockwise while only 105 were rotating counterclockwise. The analysis shows a 3.39 σ difference (p < 0.001). That indicates strong statistical evidence against a purely random distribution—but does not yet reach the more stringent 5 σ benchmark sometimes used in fields like particle physics.
This unexpected imbalance hints at what some call a “cosmological-scale axis” or directional bias in galaxy spins. That is, it challenges the assumption of isotropy in universal formation and evolution. The finding also dovetails with some alternative theories, including black hole cosmology, which posit that our universe could have been “born” rotating within a spinning black hole. It would thus imprint a preferred direction on galaxy spins.
[Image Credit: JADES Survey]
To identify galaxy spin orientations, Shamir’s team used a tool called Ganalyzer, which automatically transforms each galaxy image into a radial intensity plot. By detecting how the spiral arms curve, Ganalyzer can classify a galaxy as rotating clockwise or counterclockwise from our vantage point. This data-driven, reproducible method minimizes subjective bias that can arise when classification is done manually.
The pronounced excess of clockwise galaxies in the JADES sample resonates with smaller but similar signals observed in earlier, Earth-based surveys, such as analyses of more than a million galaxies in the Dark Energy Spectroscopic Instrument (DESI) Legacy Survey. According to Shamir, those studies indicated that the asymmetry might become more pronounced at higher redshifts. JWST’s deeper view also appears to support.
Complicating the debate, however, are prior studies that have argued for a fully random distribution of galaxy spins, sometimes using different or smaller data sets. Some annotated galaxies manually, risking subjective bias and limited sample sizes, while others used machine learning approaches that inadvertently removed spin-related features. Shamir’s re-examinations suggest these past data may still be consistent with a subtle but real spin asymmetry, though consensus in the field has yet to be reached.
Shamir’s paper also explores an alternative explanation that isn’t about cosmic origin but observational bias. “If the physics of galaxy rotation affects the brightness of the galaxy in a manner that is currently unknown, that can also affect the redshift,” Shamir noted. This Doppler effect/observational bias explanation would suggest galaxies rotating opposite to the Milky Way might appear brighter from Earth, making them more detectable at greater distances.
Shamir also emphasizes that this asymmetry peaks specifically near the Galactic poles, with opposite patterns at each pole.
As with any high-profile cosmological result, more exploration is required to determine definitively whether this effect arises from a true large-scale axis or is instead explained by observational factors such as Doppler bias from our vantage point in the Milky Way. If the asymmetry truly reflects a cosmological-scale structure, it would challenge the Cosmological Principle. The coming years of JWST data gathering and additional surveys should illuminate whether these initial findings hint at a deeper cosmic alignment or simply reflect subtler effects in galaxy brightness and detection thresholds.
