Astronomers have directly observed how turbulent gas and charged particles floating between stars can bend and distort light traveling across the galaxy.
The discovery gives scientists a new way to study the hidden structure of the Milky Way and could eventually help produce clearer images of the giant black hole at the center of our galaxy.
The research was led by scientists at the Center for Astrophysics | Harvard & Smithsonian and published in The Astrophysical Journal Letters.
The space between stars is not empty. It contains clouds of gas, dust, and free electrons known as the interstellar medium.
This material is constantly moving and swirling in a chaotic way, creating turbulence throughout the galaxy.
When radio waves from distant objects travel through this turbulent region, the waves become distorted. Scientists compare the effect to the shimmering air above a hot fire or the wavy appearance of objects seen through heat rising from a road on a hot day.
Astronomers have known for many years that this turbulence exists because they could see its effects on incoming radio signals. However, directly studying the structure of the turbulence itself has been extremely difficult.
To investigate the problem, researchers focused on a very bright object called quasar TXS 2005+403. Quasars are powered by enormous black holes located at the centers of distant galaxies. This particular quasar lies about 10 billion light-years away from Earth in the constellation Cygnus.
As radio light from the quasar traveled toward Earth, it passed through one of the most turbulent regions of the Milky Way. The scientists expected the turbulence to simply blur and weaken the radio signal.
Instead, they found something much more interesting.
Using nearly ten years of archived data from the National Radio Astronomy Observatory’s Very Long Baseline Array, a network of ten radio telescopes spread across the United States, the team discovered that the radio signal contained persistent patchy structures and unusual distortions.
These patterns could only be explained by turbulence in the interstellar medium.
Lead researcher Alexander Plavin explained that much of what the telescopes detected was not actually coming directly from the quasar itself, but from the way the turbulent gas in the Milky Way scattered and bent the radio waves.
The discovery is important because it gives astronomers a new tool for understanding how energy and matter move through the galaxy. The turbulent structures they detected are roughly the size of our solar system and may influence how clouds of gas eventually collapse to form new stars.
The findings may also help scientists improve images of Sagittarius A*, the supermassive black hole at the center of the Milky Way. Current images taken by the Event Horizon Telescope Collaboration are partially blurred by the same kind of interstellar scattering.
By learning exactly how turbulence distorts radio waves, astronomers hope they can eventually remove some of that distortion and create sharper images of black holes in the future.
The research team has already started a new observing campaign that will continue through 2026 to further track how this turbulent “screen” changes over time as the gas moves through space.
