Giant ‘bubble’ in space could be source of powerful cosmic rays

A turbocharged galactic accelerator could produce the Milky Way’s most powerful cosmic rays. The origin of these ultra-fast particles is hard to pin down because they bounce off magnetic fields, so their flight paths are difficult to follow. To get around the problem, researchers measure particles that are produced when cosmic rays hit interstellar gas and that travel in straight lines. One huge gamma-ray-emitting bubble was detected within a star-forming region in the Cygnus constellation.