Voyager 2 sensed the approach of the interstellar medium

NASA / JPL-Caltech

Since late August, detectors aboard the Voyager-2 began to record an increase in the energy of cosmic rays, which means that the probe is close to the heliosphere limits and will become the second man-made object that has entered the interstellar space in the near future, reports NASA. According to scientists, the device can go into the interstellar medium around the end of December.

Probe “Voyager-2” was launched to study the solar system in 1977. The device was able to get close to all four giant planets and explore them, and then headed to the outskirts of the solar system. It was planned that the probe will work no more than five years, but in August 2018, its mission celebrated its 41th anniversary. Now the device is at a distance of more than 118 astronomical units from the Earth (the most distant man-made object is Voyager-1, the distance to which is almost 144 astronomical units)

Since 2007, the probe has been located in the outer layer of the heliosphere (a region of space where the main component of the medium is the solar wind and the magnetic fields of the sun). At the border of the heliosphere, known as the heliopause, the solar wind speed drops to almost zero. Even further, at a distance of more than 200 astronomical units from the Sun, is locatedhead shock wave, on which particles of interstellar wind begin their deceleration. As soon as Voyager-2 goes beyond the heliosphere, it will become the second human-made object (after Voyager-1) to be in interstellar space.

Since the end of August, the CRS (Cosmic Ray Subsystem) cosmic ray detectors and the Low-Energy Charged Particles LECP (Low-Energy Charged Particles) detection system onboard the probe began to detect an increase in the energy of the registered charged particles. In May 2012, similar changes in the parameters of cosmic rays were discovered by Voyager-1, it happened about three months before the spacecraft entered interstellar space, which suggests that Voyager-2 is close to the interstellar medium. less, it should be borne in mind that the devices are located in different areas of the heliopause, and the size of this area depends on the 11-year cycle of solar activity, so for now scientists cannot say exactly when the probe will reach the heliopause.

“When Voyager 1 approached the Heliopause, then about two months later, unusual changes in the parameters of the cosmic rays, which the apparatus measures, began. Voyager has several detectors that record the number of particles of the solar wind and galactic particles arriving in the solar system from the outside, and their number has begun to change. In late August – early September, similar things began to be observed at Voyager 2, ”said Vladislav Izmodenov, professor of Moscow State University, head of laboratories at the Space Research Institute of the Russian Academy of Sciences , told N + 1 , who participates in data analysis from Voyagers.“These changes may mean that Voyager-2 is also approaching the boundary of the heliosphere, beyond which the pressure of the solar wind can no longer hold the pressure of interstellar particles — the moment of crossing this boundary can be called the output of the apparatus into interstellar space. It is possible that by the end of December “Voyager-2” will come out of the heliosphere, ”says the scientist.

Voyagers’ record-breaking missions are making documentaries, and in more detail about the history of the project you can read in our material “ 37.6 million leagues above the water ”.

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