Video: This new movie of the supernova remnant Cassiopeia A was made by combining Chandra X-ray satellite observations taken in January 2000, February 2002, February 2004 and December 2007. (Courtesy of NASA/CXC/SAO/D Patnaude et al.)

Video: Fly through the supernova remnant Cassiopeia A in this new visualisation made from images from space- and ground-based telescopes. (Courtesy NASA/CXC/D Berry; Model: NASA/CXC/MIT/T Delaney et al.)

Cassiopeia A is the ghostly remnant of a supernova that exploded in the Milky Way some 330 years ago (Image: NASA/CXC/SAO/D Patnaude et al.)

A new video suggests that Cassiopeia A, the remnant of a supernova that exploded in the Milky Way some 330 years ago, may be channelling its energy into creating high-speed charged particles called cosmic rays.


Daniel Patnaude of the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, has assembled eight years of observations to create a time-lapse movie showing debris flying outward from the site of the explosion.

The movie has allowed Patnaude to clock the expansion speed at 4900 kilometres per second. While this is fast by human standards, it falls far short of the expected speed of 6300 km/s based on the estimated energy of the initial explosion.

So where did the missing energy go? Patnaude suggests it is being used to magnetically accelerate particles, turning them into high-speed cosmic rays, like those that bombard our planet on a daily basis. Investigations of the magnetic fields within Cassiopeia A appear to support this conclusion.

The results were presented on Tuesday at the American Astronomical Society meeting in Long Beach, California.