A Voyager 2 probe could be about to enter interstellar space, 41 years after leaving the Earth

NASA's Voyager 2 spacecraft has been traveling in space for 41 years and is currently just under 11 billion kilometers from Earth, more than 118 times the distance between the Earth and the Sun.

Now, operators believe that Voyager 2, launched from the Kennedy Space Center in August 1977, could reach the periphery of the solar system and is about to enter interstellar space.

For about ten years or so, the probe has been traveling through the outermost layer of the heliosphere, a vast spherical region of space dominated by the influence of the Sun and its magnetic field.

Once Voyager 2 has crossed the boundary of the heliosphere, called heliopause, it will become only the second object created by humans, after its twin Voyager 1, to enter interstellar space.

Since the end of August this year, the onboard instruments have seen an increase of about 5% in the cosmic ray rate on the spacecraft compared to the beginning of the month.

Cosmic rays are high-energy radiation from outside the solar system made up of rapidly moving particles. Some of these cosmic rays are blocked by the heliosphere. This is why mission planners expect to detect more of them as the probe approaches and crosses the heliopause – much like the observed increase in May 2012 by Voyager 1 about three months before entering the interstellar space. .

However, the increase in cosmic ray detection is not necessarily a definite sign that the probe is about to pass through the heliopause, according to the Voyager team. Voyager 2 is located in a region completely different from the outermost layer of the heliosphere, so it is possible that the chronology of their output from the solar system varies.

Voyager 2 is also close to the heliopause six years after pairing, which is significant as this limit moves inward and outward during the 11-year cycle of the Sun's activity.

"We are witnessing a change in the environment around Voyager 2, no doubt," said Ed Stone, Voyager project researcher, from Caltech to Pasadena, in a statement. "We will learn a lot in the months to come, but we still do not know when we will hit the heliopause – we are not there yet – that is one thing I can say with confidence. "

The two Voyager spacecraft were built by NASA's Jet Propulsion Laboratory in Pasadena, California, which still operates them.

During their stay in space, travelers revolutionized our understanding of the external solar system. Voyager 2, for example, is the only spacecraft to have been flown by the four outer planets. It was also the first to image the rings of Jupiter, Uranus and Neptune.

Meanwhile, the probes were the first to discover active volcanoes beyond the Earth on Io, the first to detect the clues of an ocean outside our planet under the icy crust of Europe and the first to to observe the lightning on another world in the midst of the violent storms of Jupiter. One can also attribute to them the identification of several new planetary moons, including 11 around Uranus.

Even though they will not approach another stellar system for at least 40,000 years, they still provide us with a fascinating glimpse of the totally unexplored region where the influence of our sun is diminishing. and where the interstellar space begins. All the more remarkable as they use a less powerful technology than an average 2018 smartphone.