Voyager 2 detects clues indicating that interstellar space is near

Six years ago, the Voyager 1 spacecraft informed scientists that it had become the first object created by humans to penetrate interstellar space. Now, Voyager 2 has begun to show signs that its own solar system exit may be coming soon.

According to a NASA statement, two of Voyager 2's instruments measured an increase in the number of high-energy particles called cosmic rays, hitting the spacecraft. Scientists believe that the heliosphere, the region of particles and magnetic fields under the influence of the Sun, blocks some cosmic rays. An increase in their speed means that the probe could approach the heliopause, the outer limit of the heliosphere.

This could be a taste of things to come. "We will learn a lot in the months to come, but we still do not know when we will hit the heliopause," said Voyager project leader Ed Stone. "We're not there yet, it's something I can say with confidence."

Travelers 1 and 2 were launched in 1977 to explore Saturn and Jupiter. Voyager 1 then began his mission in the solar system, while Voyager 2 was able to return data on Uranus and Neptune before starting his own journey of several decades. The probes made discoveries, returned important data and presented iconic images of the outer planets. Scientists continue to use the probes 40 years later, although the missions have changed: now, the spacecraft is exploring the limits of the solar system and periodically sending back data via radio waves.

Voyager 1 measured an increase in cosmic rays in May 2012 before crossing the heliopause three months later – a measurement accompanied by a sudden increase in ambient plasma density. Maybe Voyager 2 is getting closer too, though Jamie Rankin, a Princeton scientist who uses Voyager's data, told Gizmodo that Voyager 2 had not yet reached interstellar space.

Randy Gladstone, a scientist with the New Horizons mission of the Southwest Research Institute, explains why it is important to spend the blizzard with a second probe: "As with almost anything, doing something new can tell you if you really understand it. or not. The Voyager 2 crossing is in a very different place and, although the current models can adapt to it, it is almost certain that these models are too simple to get it perfectly. We still learn a lot in these situations (this is one of the main reasons we have a Voyager 1 and a Voyager 2). "

It is hard to say if Voyager 2 will leave the solar system soon. But that's another reminder of the incredible of these missions. Voyager 2 is currently 11 billion kilometers from the Sun, 118 times the distance between the Sun and the Earth. Voyager 1 is more than 13 billion kilometers from the Sun, 144 times the Sun-Earth distance. However, they can still send us interesting scientific results and, yes, explore the space even beyond the influence of the sun.