An international group of astronomers led by the Purple Mountain Observatory of the Chinese Academy of Sciences said about a discovery that changes the traditional idea of the shape of the Milky Way. Researchers have found that the disk of our galaxy is not flat: in addition to the long-known global curvature, its outer regions contain large-scale wave-like structures that scientists compare to "wrinkles."
The results of the work were published on August 7, 2026, in the journal Nature Astronomy.
Milky Way Panorama
The team used data from the large-scale Milky Way Panorama project, obtained with the 13,7-meter millimeter telescope. The analysis covered more than 30 thousand molecular clouds, which were traced by the spectral lines of carbon monoxide (CO) - one of the most important indicators of cold interstellar gas from which new stars are born.
After constructing the first comprehensive model of the deformation of the outer disk, the researchers mathematically "subtracted" the overall curvature of the galaxy. It was then that the broad wave-like structures that pass through significant areas of the outer disk and form the complex three-dimensional geometry of the Milky Way became visible.
Main results of the study
- over 30,000 molecular clouds analyzed;
- the first global 3D deformation model of the outer disk of the Milky Way was built;
- vertical waves with an amplitude of 100–200 parsecs (approximately 330–650 light years) were detected;
- the wavelength is 3,9–7,9 kiloparsecs;
- one of the largest folds extends for about 40 kiloparsecs, or about 130,000 light-years.
Plane perturbation
Scientists have also discovered that even the spiral arms of the Milky Way do not lie in the same plane. They exhibit regular vertical oscillations, confirming the much more complex spatial structure of our galaxy than previously thought.
The origin of these waves is not yet fully understood. Researchers suggest that they may be the result of so-called bending waves, which arise under the influence of external gravitational perturbations. Possible causes include the interaction of the Milky Way with dwarf satellite galaxies or the influence of dark matter on the outer regions of the galactic disk.
HiTech Expert Take
The discovery demonstrates how revolutionary modern methods of astronomical research have become, combining large-scale observations with three-dimensional modeling. While the curvature of the Milky Way disk was previously considered a single large-scale deformation, now there is evidence of a complex system of wave structures that may contain information about the history of gravitational interactions in our galaxy.
Such results are important not only for studying the evolution of the Milky Way, but also for building models of spiral galaxy formation in general. Further observations using next-generation radio telescopes and space missions will allow us to test whether such "wrinkles" are a typical feature of large disk galaxies in the universe.
