The hush of interstellar space
After several months of combing through the data with a finer and finer-toothed comb, I noticed a faint line in the PWS spectrum, which appeared to follow the plasma frequency and persisted for almost three years, beginning in 2017 and ending with the most recent publicly available data. This plasma line was unlike anything I'd seen before, extremely narrowband and so weak that it was only detectable in the absence of plasma oscillation events. Anxious to determine whether this signal was real or some kind of noise artifact, we consulted with the PWS PI Don Gurnett and Co-I Bill Kurth at the University of Iowa, who performed independent checks of the data and confirmed the validity of our detection. After much discussion with our colleagues at U. Iowa about the origin of this faint plasma line, we concluded that this signal could be used to infer the plasma frequency. For the first time, we were able to regularly trace the plasma distribution of the very local interstellar medium over almost 10 AU of interstellar space, with a spatial resolution less than 0.05 AU.
— Voyager 1 hears the hush of interstellar plasma
I think it's amazing that the Voyager 1 probe, launched in the same year as I was born, is still relaying information back home and pushing the limits of what we know about the universe around.