AGU: Voyager 1 has left the solar system, sudden changes in cosmic rays indicate “In the GRL article, the authors state: “It appears that [Voyager 1] has exited the main solar modulation region, revealing [hydrogen] and [helium] spectra characteristic of those to be expected in the local interstellar medium.” However, Webber notes, scientists are continuing to debate whether Voyager 1 has reached interstellar space or entered a separate, undefined region […]