NASA launched the Voyager 2 42 years ago on August 20, 1977, to study the solar system’s most distant planets. Since its launch, the probe has encountered several planets, among them Jupiter, Saturn, Uranus and Neptune. One year ago, on November 5, 2018, the probe entered interstellar space.
Is Voyager 2 still transmitting?
Voyager 2 left the heliosphere – a vast bubble created and maintained by the Sun – in November last year.
When it left, it had spent some 41 years in space, transmitting data back to NASA of the solar system’s outer reaches.
Now the probe has ventured into interstellar space it continues to transmit back to its NASA handlers.
Several studies of Voyager 2’s data have revealed what it discovered, after analysing data from its crossing more than a year ago.
New reports published in Nature Astronomy have revealed Voyager 2 discovered “unexpected” differences in the density of plasma, a gas made of ions and free electrons.
According to the studies, plasma in local interstellar space is denser than plasma in the heliosphere.
Voyager 2 also found the plasma in interstellar space is much colder.
Ed Stone, a Voyager project scientist since 1975, said voyager’s temperature changes are providing NASA with qualitative data about the size of the heliosphere.
He said: “Our journey has expanded deeper and deeper into space.
“We had no quantitative idea of how big this bubble is that the sun creates around itself with its supersonic solar wind, made of ionized plasma, which is speeding away from the sun in all directions.
“And we didn’t know the spacecraft could live long enough to reach the edge of the bubble, leave it and enter nearby interstellar space.”
