Washington, DC, United States (4E) – The NASA spacecraft Voyager 1 exited the solar system in August last year, the space agency’s officials belatedly confirmed on Thursday.
John Grunsfeld, NASA’s associate administrator for the Science Mission Directorate, made the confirmation in a news conference citing space plasma density encountered by the spacecraft as proof.
The plasma data gathered by a team of researchers led by Don Gurnett, an Iowa State plasma physicist and a Voyager project scientist, indicate that the solar system prober is already outside the heliosphere, where hot energy particles of the sun exist. In contrast, energy particles in interstellar space are cold. Gurnett’s findings were published in the journal Science on Thursday.
Before the announcement, scientists were debating on where exactly Voyager 1 is as its instrument measuring the electron density of plasma emitted by the sun and other stars stopped functioning in 1980. In interstellar space, plasma is highly dense, about 100,000 electrons per cubic yard of space. In the heliosphere, plasma is less dense or only about 1,000 electrons per cubic meter.
NASA remedied the problem by using Voyager 1′s two plasma wave antennas to detect plasma vibration during a solar flare and convert it to sound.
NASA launched Voyager 1 in 1977 with a sister aircraft, Voyager 2, following 16 days later. Based on NASA’s real-time odometer, Voyager 1 is currently 11.7 billion miles from Earth making it the farthest human-made object from Earth.
Voyager 2 is 9.5 billion miles from the planet and is expected to exit the solar system in three to four years.
Voyager 1′s speed is more than 38,000 miles per hour. With plutonium as power and a 68 kilobyte memory onboard, it communicates with NASA daily.