Space.com (December 23, 2009)
"Our solar system is passing through a cloud of interstellar material that shouldn't be there, astronomers say. And now the decades-old Voyager spacecraft have helped solved the mystery.
"The cloud is called the 'Local Fluff.' It's about 30 light-years wide and holds a wispy mix of hydrogen and helium atoms, according to a NASA statement released today. Stars that exploded nearby, about 10 million years ago, should have crushed the Fluff or blown it away.
"So what's holding the Fluff in place?
" 'Using data from Voyager, we have discovered a strong magnetic field just outside the solar system,' explained Merav Opher, a NASA Heliophysics Guest Investigator from George Mason University. 'This magnetic field holds the interstellar cloud together ["The Fluff"] and solves the long-standing puzzle of how it can exist at all.'..."
The Voyager spacecraft aren't in The Fluff yet, but they're close enough to pick up its magnetic field.
So now astronomers have a really good idea what's holding The Fluff together. Next, I figure they'll be trying to discover what's generating the magnetic field.
More, about The Fluff:
- "Dense Gas Contours Surrounding the Local Cavity: Comparison with the Soft X-Ray Background Emission Map"
brief excerpt at springerlink.com
- "The Heliosphere"
Max-Planck-Institut für Aeronomie (in English)
- "Voyager Makes an Interstellar Discovery"
NASA (December 23, 2009)
- Includes illustrations