What Is a Superbubble?

A superbubble is a large collection of superheated gases formed when numerous stars in a related system die together. Instead of creating a single supernova, the stars generate an explosion of energy and stellar winds that can create a structure hundreds of light years in diameter. Special instruments are needed to identify superbubbles, because they are not usually found in the visible spectrum. Understanding how and why such phenomena form helps researchers learn more about the nature of the universe.

Researchers spent over a century mystified by the origins of so-called cosmic rays of electrically charged particles that appeared to be everywhere in the universe. They couldn’t find a rational explanation for their origins but definitely knew they existed, and knew that planets like Earth benefited from the shielding of accompanying stars to prevent exposure to the harshest cosmic rays. Without the Sun, the Earth would be constantly battered by high-energy particles that would make life impossible.

Using telescopes that look for emissions in the gamma and x-ray range, researchers finally determined where the cosmic rays were coming from: superbubbles scattered across the universe. A superbubble forms when several stars closely clustered together die, creating multiple massive bursts of energy in the form of supernovae. In addition, they also generate stellar winds that swirl and heat gases to extremely high temperatures. Shells form, enclosing the heated gases and creating a superbubble.

The solar system actually lies at the heart of what used to be a superbubble. Researchers have identified bubbles in various regions of space by looking for their tell-tale signature. This helps them determine the age of the universe, track the formation and death of star systems, and learn more about the overall composition of the universe. Superbubbles also explain the steady source of cosmic rays that makes much of space very hostile to living organisms which cannot survive under steady exposure to high-energy particles.

Images of superbubbles can be produced by colorizing telescope data to show people the specific shape and structure of these phenomena. They are not produced in a perfect bubble shape, but rather in a cloud of gas that may be abstract in nature. Some of these conversions used to turn non-visible emissions into an understandable image are quite visually striking. Like other images from deep space, superbubble pictures are sometimes used in promotional materials for telescopes, astronomy organizations, and government agencies dedicated to space research and exploration.