Local Bubble

The Local Bubble is a roughly 300-light-year-wide cavity of hot, low-density gas in the interstellar medium surrounding the Sun. Its boundaries are traced by denser clouds and neutral gas.

Interstellar medium: The gas, dust, magnetic fields, and energetic particles occupying the space between stars. The Local Bubble is a cavity within this broader material.
Scorpius–Centaurus association: A nearby association of young, massive stars divided into the Upper Scorpius, Upper Centaurus–Lupus, and Lower Centaurus–Crux subgroups. Its massive stars are leading candidates for progenitors of explosions that helped form the Bubble.
Soft X-ray background: Diffuse X-ray emission observed across the sky at relatively low photon energies. Hot gas in and around the Local Bubble contributes to this nearby emission.
Loop I bubble: A large radio-emitting superbubble in the direction of the Scorpius–Centaurus association. It is a neighboring cavity whose boundary may interact with the Local Bubble.
Supernova: A stellar explosion that ejects material and launches shock waves into surrounding space. Supernovae are the leading explanation for the energy that excavated the cavity.
Local Bubble supernovae: The proposed sequence of nearby supernovae that excavated and heated the Local Bubble over millions of years. This reconstruction explains the Bubble's energy and evolving shell.
Interstellar extinction: The dimming and reddening of starlight as it passes through interstellar dust. The Bubble's low-density interior helps explain unusually clear sightlines to nearby stars.
Gould Belt: A tilted ring-like arrangement of young stars and star-forming regions near the Sun. Its stellar populations and history overlap with proposed sources of nearby supernovae.
Stellar wind: A continuous outflow of charged particles from a star. Winds from massive stars can help clear and heat gas before they explode.
Radioactive iron-60: A radioactive isotope of iron detected in geological and lunar samples, produced mainly by massive-star events. Its deposits on Earth provide evidence for nearby supernova activity in the Bubble's past.

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Orion ArmBroader topic: This nearby cavity occupies part of the Orion Arm around the Solar System.