What is the Local Bubble?
Q: What is the Local Bubble?
A: The Local Bubble is a relative cavity in the interstellar medium (ISM) of the Orion Arm in the Milky Way.
Q: What does the Local Bubble contain?
A: The Local Bubble contains among others, the Local Interstellar Cloud, which contains the Solar System, and the G-Cloud.
Q: How large is the Local Bubble?
A: The Local Bubble is at least 300 light years across.
Q: What is the neutral-hydrogen density of the Local Bubble?
A: The neutral-hydrogen density of the Local Bubble is about 0.05 atoms/cm3, or about one tenth of the average for the ISM in the Milky Way (0.5 atoms/cm3).
Q: What is the cause of the exceptionally sparse gas of the Local Bubble?
A: The exceptionally sparse gas of the Local Bubble is the result of supernovae that exploded within the past ten to twenty million years.
Q: What is the state of the gas in the Local Bubble?
A: The gas in the Local Bubble is still in an excited state, emitting in the X-ray band.
Q: How long ago did the supernovae that caused the Local Bubble explode?
A: The supernovae that caused the Local Bubble exploded within the past ten to twenty million years.
