You may often hear the claim that two nasa spacecraft launched in 1977, Voyager 1 and 2, have rushed out of the solar system and sailed into the vast expanse of interstellar space, farther and farther away from us, never to return.
Well, it sounds very sad, the two spacecraft carry the information and hopes of mankind, sail to the distant unknown world, become the messenger of human contact with extraterrestrial life, and are now the farthest man-made objects made from Earth in human history.
As of this time today (19:40 on March 25), Voyager 1 is 23.284 billion kilometers away from Earth, and Voyager 2 is also 19.445 billion kilometers away.
What you don't know, however, is that they are not gone forever, in fact they are only away from the Earth in general, but from time to time they will still approach the Earth, wandering and stumbling.
To be precise, Voyager spends nearly 3 and a half months a year and is getting closer and closer to Earth.
What the? You may have dropped your glasses, how could that be? Doesn't it mean that Voyager 1 is leaving Earth at 61,500 km/h (17 km/s) and Voyager 2 is leaving Earth at 56,300 km/h (15 km/s), and how is it getting closer and closer in the past few months?
The reason is very simple, the Earth is orbiting the sun, and the speed is as high as 30 kilometers per second, that is, 108,000 kilometers per hour, which is much higher than the speed of Voyager.
This means that at certain times of the year, Earth will chase Voyager at a faster speed on one side of the sun, shortening the distance between them.
We take Voyager 2 as an example, every year from late February to early June, it seems to be gradually approaching Earth:
February 20, 2022 ~ 130.05518 ASTRONOMICAL UNITS
February 22, 2022 to 130.05454 ASTRONOMICAL UNITs
See? On February 20 of this year, Voyager 2 was 130.05518 AU from Earth, and two days later it was reduced to 130.05454 AU, close to 96,000 km from Earth.
June 2, 2022 to 129.72179 ASTRONOMICAL UNITS
June 4, 2022 - 129.72224 ASTRONOMICAL UNITS
It wasn't until June 2 that it began to move away from Earth again, at a distance of 129.72179 AU, a full 50 million kilometers closer to Earth than on February 20, equivalent to one-third of the distance between Earth and the Sun!
Of course, if we use the distance between Voyager and the Sun, this problem does not exist.
As of today, the Voyager 1 nuclear battery has 70.32% of the plutonium-238 fuel left, and about 56.5% of the fuel will remain by 2050.
However, due to the decline in battery power, Voyager has shut down most of the scientific instruments, and only 4 and a half magnetometers for measuring magnetic fields are still in operation, and between 2025 and 2030, there may not be enough power to supply any instruments, and it will completely lose contact with us. Voyager 2 is more or less the same, after which they will fly silently, alone, into the deep space of the universe, and the real thing is gone.
At present, through the high-gain antenna of the 3.7-meter-diameter parabolic antenna on the spacecraft, Voyager is still sending a weak signal to Earth, which is received by NASA's three deep space communication facilities in the United States, Spain and Australia every 120 degrees, and it takes 21.5 hours (Voyager 1) or 18 hours (Voyager 1) to reach Earth.
This photo is called the dim blue dot, which is taken by Voyager 1 looking back at the earth 6.4 billion kilometers away, and it is the photo of the earth taken by humans from the farthest place so far, and the color stripes are the spots of light produced by the sunlight in the lens.
All of us live on this little blue dot, like a grain of dust, how small and fragile it seems in the vast universe, and if something goes wrong with it, we will have nowhere to go.
However, many people still do not cherish it, constantly heating it with fossil fuels, constantly destroying the life it carries with tank cannons, and even trying to use nuclear bombs to make all life zero.
How shameful, in addition to this dark blue dot, there is only a boundless darkness around, which is all we have, the only home, the only dwelling place, why do we always have to set off a bloody storm?