NASA's probe crosses into interstellar space

WASHINGTON - Voyager 2, a NASA probe launched in 1977 and designed for just a five-year mission, has become only the second humanmade object to enter interstellar space as it continues its marathon trek billions of kilometers from Earth, scientists said on Monday.

Data from instruments aboard the spacecraft showed it crossed the outer edge of the heliosphere, a protective bubble of particles and magnetic fields produced by the sun, on Nov 5, the US space agency said.

The boundary crossed by the intrepid probe as it journeys a bit more than 18 billion km from Earth is called the heliopause, a place where the hot solar wind runs up against the interstellar medium, the soup of stuff residing between the stars of our Milky Way galaxy.