科技英语新闻:Solar system edge filled with sea of magnetic bubbles: JPL

LOS ANGELES, June 9 (Xinhua) -- The edge of our solar system may not be smooth, but filled with a turbulent sea of magnetic bubbles approximately 100 million miles (160 million kilometers) wide, NASA's Jet Propulsion Laboratory (JPL) said on Thursday.

The finding was based on observations from NASA's Voyager spacecraft, humanity's farthest deep space sentinels, said JPL in Pasadena, Los Angeles.

While using a new computer model to analyze Voyager data, scientists found the sun's distant magnetic field is made up of bubbles which are created when magnetic field lines reorganize, said JPL.

The new model suggests the field lines are broken up into self- contained structures disconnected from the solar magnetic field, according to JPL.

"The sun's magnetic field extends all the way to the edge of the solar system," said astronomer Merav Opher of Boston University. "Because the sun spins, its magnetic field becomes twisted and wrinkled, a bit like a ballerina's skirt. Far, far away from the sun, where the Voyagers are, the folds of the skirt bunch up."

Like Earth, our sun has a magnetic field with a north pole and a south pole. The field lines are stretched outward by the solar wind, a stream of charged particles emanating from the star that interacts with material expelled from others in our corner of the Milky Way galaxy.

Understanding the structure of the sun's magnetic field will allow scientists to explain how galactic cosmic rays enter our solar system and help define how the star interacts with the rest of the galaxy.

The Voyager spacecraft, more than nine billion miles (14 billion kilometers) away from Earth, are traveling in a boundary region. In that area, the solar wind and magnetic field are affected by material expelled from other stars in our corner of the Milky Way galaxy.

Launched in 1977, the Voyager twin spacecraft have been on a 33- year journey. They are en route to reach the edge of interstellar space. JPL built the spacecraft and continues to operate them.