If anyone accuses you of “living in a bubble” there is an astronomically correct, if not always convincing, response: we all do. The Sun sits inside what is known as the Local Bubble, a space within the Milky Way galaxy some 1,000 light-years across in which interstellar material is scarce. It can be hard to map something from the inside, but that’s what astronomers have tried to do with the Local Bubble’s magnetic fields.
It’s easy to imagine that anything distinctive about our Solar System’s location must be connected to our apparent uniqueness. However, superbubbles like our own are not particularly rare; indeed, the galaxy has enough of them to prompt comparisons with Swiss cheese. They are left behind by supernova explosions that push gas and dust out of surrounding regions. The material swept out by the explosion concentrates on the bubble’s surface – still so thin it would be considered a vacuum by Earthly standards, but dense enough to trigger star formation.
Nevertheless, our knowledge of superbubbles in general and the Local Bubble, in particular, is almost as thin as the material inside. The magnetic mapping of the Local Bubble, presented at the American Astronomical Society’s 241st meeting, is an attempt to address that.
