Researchers at the University of Iowa report that the spacecraft Voyager 2 has entered the interstellar medium (ISM), the region of space outside the bubble-shaped boundary produced by wind streaming outward from the sun. Voyager 2, thus, becomes the second human-made object to journey out of our sun’s influence, following Voyager 1’s solar exit in 2012.
Gurnett, professor emeritus in the UI Department of Physics and Astronomy, is the principal investigator on the plasma wave instrument aboard Voyager 2. He is also the principal investigator on the plasma wave instrument aboard Voyager 1 and authored the 2013 study published in Science that confirmed Voyager 1 had entered the ISM.
Data from the Iowa instrument on Voyager 2 also gives additional clues to the thickness of the heliosheath, the outer region of the heliosphere and the point where the solar wind piles up against the approaching wind in interstellar space, which Gurnett likens to the effect of a snowplow on a city street.
The Iowa study is one of five papers on Voyager 2 published in Nature Astronomy. These papers confirm the passage of Voyager 2 to interstellar space and provide details on the characteristics of the heliopause.
Gurnett and Kurth are the study’s sole authors. Their research was funded by NASA, through a contract with the Jet Propulsion Laboratory.