According to an August 15 news release from the University of Maryland in College Park, scientists from the academic institution speculate that NASA’s Voyager 1 spacecraft appears to have left our solar system and entered into interstellar space. The Voyager 1 spacecraft carries greetings from Earth in several languages on a gold-plated record-player, as well as operational scientific instrumentation. The spacecraft has traveled farther from our planet than any other man-made object.
According to University of Maryland research scientist Marc Swisdak, the lead author of a paper published this week in the online issue of The Astrophysical Journal, “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.” Swisdak and his colleagues built a model of the outer edge of the Solar System that falls in line with recent observations, and incorporates both expected and surprising details.
According to this model, the Voyager 1 spacecraft exited our Solar System over one year ago. The finding challenges recent publications by NASA and other scientists that the spacecraft is in a poorly-defined “transition zone” at the edge of our Solar System.
Ed Stone, NASA’s Voyager project scientist of the California Institute of Technology in Pasadena, California, reacted to the publication, saying, “Details of a new model have just been published that lead the scientists who created the model to argue that NASA’s Voyager 1 spacecraft data can be consistent with entering interstellar space in 2012. In describing on a fine scale how magnetic field lines from the sun and magnetic field lines from interstellar space can connect to each other, they conclude Voyager 1 has been detecting the interstellar magnetic field since July 27, 2012. Their model would mean that the interstellar magnetic field direction is the same as that which originates from our sun.”
Swisdak and his colleagues challenged conventional wisdom as to what the transition across the boundary should look like to observers 11 billion miles away on Earth. Our Sun’s heliosphere is fairly well-understood as the portion of space ruled by the magnetic field and charged particles coming from our Sun, but the heliopause transition zone is not well-understood. In the summer of 2012, NASA scientists encountered observations of never-before-seen particles, and theorized that the Voyager 1 spacecraft entered a so-called “heliosheath depletion region.” However, the scientists did not go so far as to say that the spacecraft crossed the heliosphere into interstellar space.
Swisdak and his colleagues instead suggest that the heliopause is layered and porous, and this sentiment is reflected in their paper, entitled, “A POROUS, LAYERED HELIOPAUSE.”