Matthew Rozsa reports at Salon that the radio signals that humans have sent the farthest distance may be having problems getting any further. On Sept. 5, 1977, NASA launched the Voyager 1 space probe, which has now traveled 14.5 billion miles away from Earth. Radio signals to and from the Voyager 1 now take 20 hours and 33 minutes to reach each other. Voyager 1 is so far away it has left our universe, and is now in the interstellar void of the Milky Way. But it is losing power, and the interstellar void seems to be creating havoc. "The interstellar explorer is operating normally, receiving and executing commands from Earth, along with gathering and returning science data," NASA said on its website. "But readouts from the probe's attitude articulation and control system (AACS) don't reflect what's actually happening onboard." Suzanne Dodd, project manager for Voyager 1 and 2 at NASA's Jet Propulsion Laboratory in Southern California, explains further. "We're also in interstellar space – a high-radiation environment that no spacecraft have flown in before. So there are some big challenges for the engineering team. But I think if there's a way to solve this issue with the AACS, our team will find it." The Voyager 1 probe is so far into space that astronomers can now hear the "hum" that our solar system produces as the spacecraft travels outside of it. The hum is "interstellar gas," also known as plasma waves, "It's very faint and monotone, because it is in a narrow frequency bandwidth," said Stella Koch Ocker, a doctoral student in the Department of Astronomy and Cornell Center for Astrophysics and Planetary Science. "We're detecting the faint, persistent hum of interstellar gas." Scientists may keep hearing that hum through 2025, when the radioisotope thermoelectric generators will no longer have enough energy to keep transmitting. Read more about this story at Salon.