Local Interstellar Cloud


The Local Interstellar Cloud, also known as the Local Fluff, is the interstellar cloud roughly across, through which the Solar System is moving. It is unknown if the Sun is embedded in the Local Interstellar Cloud, or in the region where the Local Interstellar Cloud is interacting with the neighboring G-Cloud.

Structure

The Solar System is located within a structure called the Local Bubble, a low-density region of the galactic interstellar medium. Within this region is the Local Interstellar Cloud, an area of slightly higher hydrogen density. The Sun is near the edge of the Local Interstellar Cloud. It is thought to have entered the region at some point between 44,000 and 150,000 years ago and is expected to remain within it for another 10,000 to 20,000 years.
The cloud has a temperature of about, about the same temperature as the surface of the Sun. However, its specific heat capacity is very low because it is not very dense, with. This is less dense than the average for the interstellar medium in the Milky Way, though six times denser than the gas in the hot, low-density Local Bubble which surrounds the local cloud. In comparison, Earth's atmosphere at the edge of space has around 1.2 molecules per cubic centimeter, dropping to around 50 million at.
The cloud is flowing outwards from the Scorpius–Centaurus Association, a stellar association that is a star-forming region.
In 2019, researchers found interstellar iron in Antarctica which they relate to the Local Interstellar Cloud.

Interaction with solar magnetic field

In 2009, Voyager 2 data suggested that the magnetic strength of the local interstellar medium was much stronger than expected. The fact that the Local Interstellar Cloud is strongly magnetized could explain its continued existence despite the pressures exerted upon it by the winds that blew out the Local Bubble.
The Local Interstellar Cloud's potential effects on Earth are prevented by the solar wind and the Sun's magnetic field. This interaction with the heliosphere is under study by the Interstellar Boundary Explorer, a NASA satellite mapping the boundary between the Solar System and interstellar space.