On September 5, 1977, Voyager 1 set off from Earth, and its speed exceeded the speed of the third universe, which gave it the opportunity to leave the solar system.
After flying 20 years from Earth, it caught up with Pioneer 10 as the farthest man-made spacecraft from the sun and has remained so to this day — a title that will likely continue for a long, long time.
There are two most famous reports about Voyager 1:
In 1990, it took the furthest picture of the earth at a distance of 6 billion kilometers from the earth - the dim blue dot, which is the most artistic value;
Note: Dim blue dot
And the overwhelming news reports in 2012 that it became the first man-made spacecraft to fly out of the solar system and into interstellar space, which was one of the most landmark events.
So, how big is the solar system? Has Voyager 1 really flown out of the solar system?
How big is the solar system?
While solar system size can be defined in several different ways, either way, our solar system is unimaginably large in terms of humans and Earth.
Note: True proportions of solar system members
When it comes to huge astronomical distances, which are astronomical, our ordinary way of counting seems a little small, so astronomers create astronomical units (AU) to represent these distances, and 1 AU represents the average distance from the Earth to the Sun, which is almost 150 million kilometers.
The Location of the "Dim Blue Dot" is almost 40 AU from Earth, and Voyager 1 flew for more than 12 years to reach this location.
Note: Voyager 1's trajectory
It is said that many people will feel the smallness of humans when they see the "dim blue dot", because the earth at this distance is not even a pixel.
Some people think that the size of the solar system should be cut up to the orbit of Neptune, which is the farthest planet from the sun among the eight planets, and its aphelion point is almost 30.33 AU, which is the radius of the solar system under this algorithm.
If according to this algorithm, the "dim blue dot" is already a photo taken outside the solar system, so it is reasonable that the Earth looks small.
Where does Voyager 1 fly away from the solar system?
Many media outlets say voyager 1 has flown out of the solar system, in fact referring to its passage through the heliopause, where the pressure of the solar wind is equal to the reverse pressure of the interstellar medium.
The solar wind, a stream of charged particles emitted outward from the Sun, is a plasma that extends all the way outward and extends far beyond neptune's location.
At the same time, interstellar plasma from the universe has been infiltrating the sun, and the solar wind acts like a magnetic field created by the earth to block the penetration of interstellar media.
Figure Note: Notes on several areas made by the solar wind
The solar wind creates a large, bubble-like area around the sun, which is called the heliosphere (some places write the solar layer).
The place where the solar wind and the interstellar medium come into contact is called the terminal shock layer, and from the terminal shock layer, the solar wind continues to be weakened by the interstellar medium, completely stopping at the top of the heliosphere, and this area where the solar wind and the interstellar medium work together is called the sun sheath.
The heliosphere protects the entire solar system from a large number of harmful cosmic rays from outside the system, but with the exception of uncharged gamma rays, so gamma-ray bursts (stars burning out and collapsing to form) are very dangerous and are even considered one of the potential risks of destroying Earth's civilization.
Since the effects of the solar wind end at the top of the heliopause, many astronomers believe that the size of the heliosphere should be the size of the solar system.
According to this algorithm, the radius of the solar system is around 100 AU, and voyager 1 took nearly 35 years to fly out.
Note: The heliosphere moves in the interstellar medium
Voyager 1's next stop: Oort Cloud
Although the scope of the solar wind's influence is very limited, the scope of the influence of the sun's gravity is very wide, in fact, the scientific consensus is that the solar system should end where the sun's gravity is not dominant.
In the outermost periphery dominated by the Sun's gravity, there may be a very wide area similar to the asteroid belt between Mars and Jupiter.
In the 1950s, the Dutch astronomer Ault introduced the concept and named the area after the Ault Cloud.
Because it is so far away from the sun, the sunlight reflected by any material in this region is so weak that even if we use the largest telescope on Earth today, it is basically impossible to observe.
However, the area is very "lively", as like the asteroid belt, because the periodic comets we now know basically originated in the Oort cloud.
In the calculation of the sun's gravity, as well as the orbital observations of periodic comets, scientists believe that with the sun as its center, the Oort cloud begins at 2000 AU and ends at 200,000 AU.
At this time, using "astronomical units" to measure distances seems to be a bit insufficient, so it can be converted into light years (the distance traveled by light in one year), and the distance of the Oort cloud is between 0.03 and 3.2 light years.
Then the scientific definition, the radius of the solar system should be about 3.2 light years, beyond this, the gravitational pull of other celestial bodies will be stronger than the sun, and other matter outside this will not belong to the material of the solar system.
Voyager 1 is now about 145 AU away from us, and it's moving away from the Sun at a speed of about 60,000 kilometers per hour, so it will enter the Oort Cloud in 550 years, and then travel through the Oort Cloud for about 60,000 years before it flies out of the solar system and truly enters the outer space of the solar system.
At last
As available power decreased, Voyager 1 had to gradually shut down some instruments, and for now, as part of power management , the heaters and other spacecraft systems have all been shut down, and it is expected that after 2025 it will shut down all instruments, and it is estimated that there will be no "audio" of it from now on.
Voyager 1 is not set to visit a single star, but in 40,000 years, it will fly by about 1.6 light-years from Gliese 445.
Voyager 1 will then become an artificial spacecraft from the solar system that is closer to another star than the Sun.