The twin planetary probes, Voyager 1 and 2, launched by NASA, went into space in 1977. Jupiter, Saturn, Uranus, and Pluto were observed in sequence, and the Voyager 2, which was slower than the 1st in November 2018, finally succeeded in leaving the heliosphere.
Now, the Voyager 2 continues to send observational data to Earth, moving at a speed of 15.65 kilometers per second through the interstellar space that spreads between stars and stars. Among the artifacts created by mankind, the heavy probe that has been active for 42 years in a place farthest from mankind has seen what he saw in interstellar space.
According to NASA, the heliosphere is the range of charged particles emitted from the sun, the solar wind, and the solar magnetic field. The solar wind blowing outward from the sun collides with the interstellar wind blowing in the opposite direction in interstellar space. This impacting interface is the termination shock. The power of the solar wind is greatly reduced here and completely disappears when it reaches the heliopause. The solar crest is the boundary line that divides the heliosphere and the star space, and in front of it is the interstellar space.
NASA says the heliosphere is like a ship sailing in interstellar space. The orbiting solar system moves with the vortex of our galaxy. It envelops the planets around the sun and proceeds in space while blocking the interstellar wind or spacecraft. It is also believed to have a long tail like a comet, but this has never been confirmed so far.
However, Voyagers 1 and 2 safely crossed the end of the shock wave plane and protruded into the interstellar space beyond the solar crest. Fortunately, 42 years later, the observation equipment onboard the Voyager still works. Of course, one of the plasma observation equipment mounted on the Voyager 1 has been disabled since 1980.
The Voyager 2 is equipped with a device that observes magnetic fields, spacecraft, plasma, and plasma waves, and allows you to obtain valuable data that tells you what interstellar space is. Based on these data, five papers were simultaneously published in the journal Nature Astronomy. Through this, the shape of the heliosphere that was almost predicted is known.
First, the plasma density increased by 20 times as it changed from solar distance to interstellar space. When the Voyager 1 broke through the solar crest, it is largely consistent with the situation scientists had already speculated. Voyager 1 and 2 passed through the solar plane at about the same distance from the Sun, even though they were 150 astronomical units in distance, that is, 150 times the distance between Earth and Sun. It can be said that the solar cirrus has little change over time.
Of course, there are also new discoveries. In 2012, when the Voyager 1 passes through the solar sphere, it was observed that the plasma density in the interstellar space outside the heliosphere was higher than expected and the plasma was clearly compressed for some reason. When the Voyager 2 last year passed through the solar crest, the plasma temperature was even higher than expected. The high plasma density inside the solar cirrus serves to reinforce the compression theory, but the problem is that we do not yet know why it is compressed.
According to NASA, if the heliosphere is a ship floating in interstellar space, it seems that there are leaks all over the hull. The Voyager 1 broke through the bow of the ship, but the Voyager 2 broke through the side of the ship, and at this time, it was discovered that some particles were leaking from the heliosphere. The prow is sturdy, but the side may be surprisingly highly permeable. This also seems to be related to the heliosphere shape.
In addition, it was found that the magnetic field is in parallel between the inside and outside of the heliosphere along the solar crest. This was also observed in Voyager 1, but since it could only be observed once, it is difficult to determine whether it is universal or coincidental.
It is said that it is of great significance that the same results were observed when the Voyager 2 broke through the solar cirrus from another location. Unfortunately, there seems to be no explanation about the fact that the heliosphere has a comet-like tail.
Voyager’s undisputed journey will continue in the future. Of course, it is also true that their lifespan is over. How efficiently the remaining fuel is used determines the Voyager’s lifespan. In any case, it can be seen that while Voyager is in operation, observations are collected and an understanding of the interstellar space that mankind has never encountered and the heliosphere that protects us will increase. Related information can be found here .
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