Artist’s rendering of the Voyager 2 spacecraft as it studies the outer limits of the heliosphere — a magnetic ‘bubble’ around the Solar System that is created by the solar wind. Scientists observed the magnetic bubble is not spherical, but pressed inward in the southern hemisphere. Credit: NASA/JPL
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 has 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 Fluff is much more strongly magnetized than anyone had previously suspected,” Opher said. “This magnetic field can provide the extra pressure required to resist destruction.”
Opher and colleagues detail the discovery in the Dec. 24 issue of the journal Nature.