From Wikipedia, the free encyclopedia

The Local Interstellar Cloud, casually called the Local Fluff, is the interstellar cloud (roughly 30 light years across) through which the Solar System is currently moving. The Solar System 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 thin, with 0.1 atoms per cubic centimeter; approximately one-fifth the density of the galactic interstellar medium (0.5 atoms/cc) and twice that of the gas in the Local Bubble (0.05 atoms/cc), the Local Bubble being 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, with a few other local stars, is embedded in the Local Fluff. Notable nearby stars include 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]

See also

• Gould Belt
• Orion Arm
• Perseus Arm

Notes

http://science.nasa.gov/headlines/y2009/23dec_voyager.htm

References

• Science Nasa: "Near-Earth Supernovas"
• Science Nasa: "A Breeze from the stars" Interstellar helium-enriched wind from Ophiucus.
• Science Nasa: Astronomy Picture of the Day
• "Local Chimney and Superbubbles"
• Mark Anderson, "Don't stop till you get to the Fluff", New Scientist no. 2585, 6 January 2007, pp. 26-30