Local Bubble

Spin view local bubble with stars

Localbubble formation

Localbubble

Local Bubble is a region of the interstellar medium in the Orion Arm of the Milky Way galaxy. It is a cavity in the interstellar medium (ISM) filled with hot, ionized gas, which is thought to have been created by several supernovae explosions within the last ten to twenty million years. The bubble is roughly spherical and has a diameter of about 300 light-years. The Sun, along with the Solar System, is currently located near the edge of the Local Bubble.

Formation

The Local Bubble's formation is attributed to the cumulative effects of multiple supernovae explosions. These massive stars ended their life cycles in spectacular explosions, releasing vast amounts of energy and ejecting their outer layers into space. This process created shock waves that swept up and heated the surrounding interstellar medium, carving out a bubble-like cavity. The interior of the Local Bubble is filled with a hot, low-density gas, which emits X-rays, making it detectable by X-ray observatories.

Characteristics

The Local Bubble is characterized by its low density of matter. The typical density inside the bubble is about 0.005 atoms per cubic centimeter, which is significantly lower than the average for the interstellar medium in the Milky Way. The temperature of the gas inside the bubble is estimated to be between one and two million degrees Kelvin, which is much hotter than the typical temperature of the interstellar medium.

Impact on the Solar System

The location of the Solar System near the edge of the Local Bubble has implications for the environment of Earth and the other planets. The bubble's low-density interior provides a relatively clear path for cosmic rays to reach the inner Solar System, which can influence the rate of cosmic ray spallation in the Earth's atmosphere and thus affect the climate. Additionally, the interaction between the solar wind and the interstellar medium at the boundary of the Local Bubble can influence the shape and size of the heliosphere, the protective bubble created by the solar wind that envelops the Solar System.

Exploration and Study

The study of the Local Bubble is conducted through observations in various wavelengths, including X-ray and ultraviolet observations. These studies help astronomers understand the properties of the hot gas within the bubble, as well as the processes that led to its formation. Understanding the Local Bubble also provides insights into the larger-scale structure of the Milky Way's interstellar medium and the lifecycle of stars.

See Also

• Interstellar medium
• Supernova
• Orion Arm
• Milky Way
• Solar System
• Cosmic rays