Voyager 1 was launched in September of 1977 and successfully completed its mission of a grand tour of Jupiter and Saturn. Now, 35 years later, it has become the first man-made device to leave the solar system.
Although Voyager 1 has long since stopped sending back images, it still transmits data on plasma density, solar wind speed and magnetic fields back to researchers on Earth. Equipped with minimal technology and memory by today’s standards, Voyager 1 is running on a nuclear power source that should last until 2025, according to NPR.
The heliosphere marks the boundary of the solar system where plasma densities, magnetic fields and winds are all expected to change. The data Voyager 1 has sent back confirms such a change in plasma densities, but not a change in the magnetic field. This unexpected occurrence has sent heliophysicists back to the drawing board, according to Science.
The Voyager 1 NASA team believes that the increase in plasma density is evidence enough to conclude that Voyager 1 has left the solar system. According to NASA, the team believes the current model of the heliosphere should be redone to assume that the magnetic fields align with each other across the boundary of the solar system.
“The change in the density is a good indication of the Voyager entering the interstellar medium,” Prof. Richard Lovelace, Department of Applied Engineering and Physics, said.
However, a handful of scientists think the change in plasma density is the result of reaching the near boundary of the heliosphere and that Voyager 1 has not conclusively left the solar system until a change is seen in the magnetic field, according to Science.
In any case, Voyager 1 is still over 11 billion miles from Earth, the farthest mankind has sent anything, and the Voyager 1 team is ramping up data collection. To do this, according to the New York Times, NASA had to bring back a 77-year-old retired engineer, Edward Stone, who is one of the few people alive that understands how to write code for such an ancient machine.
Voyager 1 entered the “turbulent zone” in 2005, nearing the edge of the Sun’s solar winds and crossing into interstellar space on August 25, 2012, according to the Voyager team. Voyager 1 is now headed to Ursa Minor or, as we know it, one of the stars in the Little Dipper, and is expected to come within two light years from it in 40,000 years.
Long before that happens, Voyager 1’s nuclear power supply will run out, ending its communication with Earth. However, a committee chaired by Carl Sagan, former professor of astronomy at Cornell, developed a time capsule of pictures and music from “Earth-people” that is in the Voyager for any intelligent life that may encounter the spacecraft in the future.