The Local Interstellar Cloud (or Local Fluff) is the interstellar cloud roughly 30 light years across through which the Earth's solar system is currently moving. The Solar System is thought to have entered the Local Interstellar Cloud at some time 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 6000 °C,[1] about the same temperature as the surface of the Sun. It is very tenuous, with 0.1 atoms per cubic centimeter; approximately one-fifth the density of the galactic interstellar medium (0.5 atoms/cc), but twice that of the gas in the Local Bubble (0.05 atoms/cc). The Local Bubble is an area of low-density in the interstellar medium, with the Local Cloud a small, more dense area. In comparison, Earth's atmosphere at STP has 2.7 × 1019 molecules per cubic centimeter.
The cloud is flowing outwards from the Scorpius-Centaurus Association, a stellar association that is a star-forming region.[2]
The cloud formed where the Local Bubble and the Loop I Bubble met. The Sun is embedded in the Local Fluff, as are a few other nearby stars including Alpha Centauri, Altair, Vega, Fomalhaut, and Arcturus.
The Local Interstellar Cloud's potential effects on Earth are prevented by the solar wind and the Sun's magnetic field.[3] This interaction with the heliosphere is under study by the Interstellar Boundary Explorer (IBEX), a NASA satellite mapping the boundary between the Solar System and interstellar space.
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