Supernovae are created from the explosions of the largest stars in the Universe, and the remnants they leave behind may be shaped by bubbles formed from radioactive metal.

Cassiopeia A is a supernova which was seen from Earth 340 years ago. Astronomers studying pockets within the gaseous remains of the extinct star believe the features may have been formed by the movement of radioactive nickel through the cloud.

When matter first formed in the early Universe, the only elements created were hydrogen, which made up the bulk of matter, helium, and a tiny amount of lithium.  Every other element we see around us today, including carbon, oxygen, and nitrogen, were all created in supernova explosions.

Cassiopeia A, commonly known to astronomers as Cas A, lies around 11,000 light years from our home planet. Astronomers created a 3D map of the supernova remnant in order to study the features contained in the gaseous cloud. They found several massive bubbles in the remnant, which left the question of how they were created.

When the star that created Cas A exploded more than 11,000 years ago, the powerful blast sent a mixture of radioactive materials into the gas cloud surrounding the dying stellar body. Determining how the massive forces exerted by the blast interacted with surrounding matter requires virtual models that challenge even the world's most powerful supercomputers.

"We're like the bomb squad. A bomb's gone off and I want to understand how that bomb exploded. So when I go in the room, the first thing I'm going to say is: Where did the debris go? Did it go in all directions equally or did it go in some directions preferentially, like a pipe bomb or something? That's step one. And that's what we've done here," Dan Milisavljevic, a postdoctoral researcher at the Harvard-Smithsonian Center for Astrophysics (CfA), said.

Astronomers involved in the research utilized the 13-foot telescope at Kitt Peak Nation Observatory in Arizona to take images of Cas A and record movement of gas within the structure, using spectroscopy, which allowed them to see the object in three dimensions.

Around half a dozen cavities can be seen in the supernova remnant, and the two most well-defined of these features measure three and six light years across. Milisavljevic and his team have stated that radioactive nickel will decay into iron, and if that material is found in the remnant in the correct concentrations, the finding could help confirm the theory.

Researchers believe their examinations of gaseous caverns within Cassiopeia could help astronomers understand the processes which trigger supernovae.

An interactive version of the 3D map of Cassiopeia A is available on the Harvard-Smithsonian Center for Astrophysics Web site.