Wednesday , January 20 2021

The Sun in the Rearview Mirror, Voyager 2 is in interstellar space

The experiment of plasma science and the change in the solar wind she discovered, as Voyager 2 reached the interstellar space.
Zoom in / The experiment of plasma science and the change in the solar wind she discovered, as Voyager 2 reached the interstellar space.

On Monday, NASA announced that one of the longest experiments has begun a new phase. Five years after Voyager 1 reached the interstellar space, his brother, Voyager 2, joined him. While the cloud cloud of ice bodies extends far beyond the current locations of the probes, they pass through the point where the charged particles of the solar wind dominate the space. Instead, their current environment is dominated by cosmic rays ejected by other stars.

Voyager 2 was actually the first of the two probes to be shot in 1977, but his trajectory had reached its first destination, Jupiter, after Voyager 1. Its final position had a great impact on its future; after Voyager 1 received enough data in Saturn, Voyager 2 had switched from a route that optimized data collection to the one who sent it to the circular planet on a trajectory that reinforced it to Uranus and Neptune. This difference means Voyager 1 has reached interstellar space much earlier.

To a great extent, it made it much easier to understand that Voyager 2 made the transition. Before Voyager 1 arrived, two transitions were expected to occur at about the same time: the magnetic field of the sun would fall and the galactic magnetic field would dominate and the particles of the solar wind would fall as the cosmic rays would rise, Voyager 1 survived the last transition, but not the first one. Put differently, there was a change in the charged particles without an accompanying change in the magnetic field.

In early November, Voyager 2 experienced the same transition at about 16.5 light hours from the Earth (about 18 billion kilometers or 11 billion miles). As the power of the solar wind fluctuates, there is a chance that the limit will catch up again before entering the interstellar space for an indefinable journey between the stars. But it will simply give scientists another chance to study the transition zone. Still, we may have a transition from the magnetic field to look forward to if the craft power lasts long enough.

Both are driven by the disintegration of a radioactive element, so their budget capacity is reduced by four watts per year. Several of their tools were closed to stay in this envelope. In the end, the power will drop low enough so the hardware can no longer communicate with the Earth.

While coming second in the race to the end of the Solar System may seem like a disappointment, Voyager 2 has a key advantage over his brother. As early as 1980, the Voyager 1 Plasma Science experiment failed; Voyager 2 is still working. The charged particles of the interstellar environment and the solar wind are plasma, which means that this hardware can measure their properties, including their velocity, density, temperature and pressure.

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