A mysterious giant wave slowly crosses the Milky Way

Credit: Ralf Konietzka, Alyssa Goodman, and WorldWide Telescope

Radcliffe waves spanning 9,000 light years are not stationary, research shows. Astronomers at Harvard University have announced new observations of Radcliffe waves, the giant structures that bend the Milky Way. Analysis revealed that this mystery not only looks like a wave, but also moves in the same way, spreading vibrations across space and time. Radcliffe waves are 9,000 light-years long wavy gas structures whose closest point is only 500 light-years from the Sun. Astronomers first reported the discovery of this wave several years ago, but at the time there was insufficient observational data to estimate how it would change over time. The researchers used the latest data from sky surveys conducted by the Gaia Space Observatory. Long-term observations show three-dimensional movement of young star clusters in Radcliffe waves. The entire massive structure vibrates and moves like what physicists call a “travelling wave.” For example, traveling waves can be observed in sports arenas when people stand up and sit down one after another. Similarly, astronomers explain that star clusters move up and down along Radcliffe waves, creating patterns that spread across the Milky Way’s disk. Observing dynamic movements can help scientists pinpoint the source of these mysterious vibrations. Existing hypotheses include external effects such as the influence of supernova explosions, the influence of dark matter, or the merger of the Milky Way and neighboring dwarf galaxies. Furthermore, the discovery of this oscillation raises questions about how common it is in the Milky Way and other galaxies, and what role it plays. Because Radcliffe waves appear to form the basis of nearby spiral arms, this oscillation could mean that the galaxy’s spiral arms are constantly moving away from the disk surface. This makes galaxies more dynamic than previously thought.

source: https://news.harvard.edu/gazette/story/2024/02/radcliffe-wave-is-waving/