Local Bubble

Milky Way superbubble

The Local Bubble, or Local Cavity, is a relative cavity in the interstellar medium (ISM) of the Orion Arm in the Milky Way. It contains the nearest stars and brown dwarfs and, among others, the Local Interstellar Cloud (which contains the Solar System), the neighboring G-Cloud, the Ursa Major moving group (List of nearby stellar associations and moving groups stellar moving group), and the Hyades (the nearest open cluster). It is estimated to be at least 1000 light years in size, and is defined by its neutral-hydrogen density of about 0.05 atoms/cm³, or approximately one tenth of the average for the ISM in the Milky Way (0.5 atoms/cm³), and one sixth that of the Local Interstellar Cloud (0.3 atoms/cm³).

From Wikipedia, under CC BY-SA. More on occurri.