Universe Today
Astronomers using the James Webb Space Telescope (JWST) have completed a survey of galaxies that reveals their rotation directions with unprecedented clarity. Contrary to expectations that galaxy rotations would be randomly distributed, they discovered a surprising pattern, that most galaxies appear to rotate in a similar direction! One hypothesis suggests the universe itself might have an overall rotation, researchers believe a more plausible explanation though is that Earth's motion through space creates an observational bias, making galaxies rotating in certain directions more detectable than others.
Galaxies are huge structures composed of billions of stars along with gas, dust, and dark matter, all bound together by gravity. These celestial giants come in various shapes, including spiral, elliptical, and irregular forms, with our own Milky Way galaxy containing approximately 100-400 billion stars. Galaxies often cluster together in groups and superclusters, creating the large scale structure of the universe that resembles a cosmic web. Galaxies are studied to understand stellar evolution, the distribution of dark matter, and the fundamental nature of the universe itself. Observatories like the JWST reveal incredible details about galactic formation and their composition.
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Spiral galaxy NGC4414 was imaged by the Hubble Space Telescope as part of the HST Key Project on the Extragalactic Distance Scale. (Credit : The Hubble Heritage Team AURA/STScI/NASA)
Just three years after launch, NASA’s James Webb Space Telescope has made a puzzling galactic discovery. According to research by Kansas State University's Professor Lior Shamir, analysis of deep space images from the Advanced Deep Extragalactic Survey reveals an unexpected pattern in the rotation of galaxies. Rather than showing random directionality, approximately two-thirds of observed galaxies rotate clockwise while only one-third rotate counterclockwise.
Artist impression of the James Webb Space Telescope (Credit : NASA)
In the study published in the Monthly Notices of the Royal Astronomical Society, researchers analysed 263 galaxies from the JADES field (the JWST Advanced Deep Extragalactic Survey) that were clear enough to determine rotational direction. According to Professor Shamir, the directional difference is so clear that anyone looking at the image would see it! It’s an observation that, in a random universe, galaxy rotation directions should be roughly equal in both directions. The study has revealed that most galaxies are rotating in the same direction.
The team proposes two main explanations for the unexpected rotation pattern. The first suggests that the universe itself was born rotating, which is also predicted by theories like black hole cosmology (which proposes our entire universe exists within a black hole) but would require current cosmological models to be revised significantly. The second explanation involves Earth's motion around the centre of the Milky Way. This movement could impose a Doppler shift effect that might make galaxies rotating opposite to Earth's direction appear brighter and more detectable, potentially creating an observational bias rather than an actual pattern.
If Earth's movement through space does indeed create this observational bias, a recalibration of deep universe distance measurements would be necessary. Such recalibration could potentially resolve other cosmological puzzles too, including discrepancies in expansion rates of the universe and the existence of galaxies that current measurements suggest are older than the universe itself!