Voyager 1 appears to have at long last left our solar system and entered interstellar space, says a University of Maryland-led team of researchers.
Carrying Earthly greetings on a gold plated phonograph record and still-operational scientific instruments – including the Low Energy Charged Particle detector designed, built and overseen, in part, by UMD’s Space Physics Group – NASA’s Voyager 1 has traveled farther from Earth than any other human-made object. And now, these researchers say, it has begun the first exploration of our galaxy beyond the Sun’s influence.
“It’s a somewhat controversial view, but we think Voyager has finally left the Solar System, and is truly beginning its travels through the Milky Way,” says UMD research scientist Marc Swisdak, lead author of a new paper published online this week in The Astrophysical Journal Letters. Swisdak and fellow plasma physicists James F. Drake, also of the University of Maryland, and Merav Opher of Boston University have constructed a model of the outer edge of the Solar System that fits recent observations, both expected and unexpected.
Their model indicates Voyager 1 actually entered interstellar space a little more than a year ago, a finding directly counter to recent papers by NASA and other scientists suggesting the spacecraft was still in a fuzzily-defined transition zone between the Sun’s sphere of influence and the rest of the galaxy.
But why the controversy?
At issue is what the boundary-crossing should look like to Earth-bound observers 11 billion miles (18 billion kilometers) away. The Sun’s envelope, known as the heliosphere, is relatively well-understood as the region of space dominated by the magnetic field and charged particles emanating from our star. The heliopause transition zone is both of unknown structure and location. According to conventional wisdom, we’ll know we’ve passed through this mysterious boundary when we stop seeing solar particles and start seeing galactic particles, and we also detect a change in the prevailing direction of the local magnetic field.
Read more at: Phys.org