First details of Voyager 2's entry into interstellar space revealed

Voyager 2's entry into the interstellar space occurred more than 18 billion kilometres from the Earth

The first analyses of communications from NASA ' s Voyager 2 probe since its entry into interstellar space in November 2018 have been published.

Researchers have revealed their findings in a series of papers published in the journal Nature Astronomy.

These five studies describe Voyager 2 ' s journey through its transition through the heliopause (part of the solar system exposed to particles and ions of deep space) and heliosheath (the region of the heliosphere beyond the termination shock) to what lies beyond in the universe.

Scientists noticed a marked jump in the plasma density tracked by the plasma wave instrument installed on the craft

The milestone achieved by Voyager 2 follows that of its twin craft Voyager 1, which accomplished the same feat in 2012.

However, there is a difference in the data collected by the two crafts during their transition from boundary of the solar system into interstellar space, as the plasma-measuring device on Voyager 1 was damaged during the course of its journey.

While analysing the data received from Voyager 2, scientists noticed a marked jump in the plasma density tracked by the plasma wave instrument installed on the craft. According to scientists, this definitive increase in plasma density confirms that Voyager 2 was moving from the hot, lower-density plasma of the solar wind to the cooler, high-density plasma, a characteristic of interstellar space.

This plasma density jump was also experienced by Voyager 1 when it entered into the interstellar space.

The two crafts crossed the heliosphere (the protective bubble of magnetic fields and particles created by the Sun) at different locations.

Voyager 2's entry into interstellar space occurred at 119.7 AU or more than 18 billion kilometres from the Earth. Voyager 1 had also entered into interstellar space at largely the same distance from the sun (122.6 AU).

"Voyager 1 exited close to the very ' front ' of the heliosphere, relative to the bubble's movement through space," NASA said.

"Voyager 2, on the other hand, is located closer to the flank, and this region appears to be more porous than the region where Voyager 1 is located," the space agency added.

Voyager 2 has not yet reached undisturbed interstellar space, according to scientists. Like Voyager 1, it is currently moving "in a perturbed transitional region" just beyond the heliosphere.