Video spoilers history, starting with the blitzkrieg on Poland

A new day, a new sky!

The image of a star first appeared on the sky.

Everyone is familiar with this star.

It is the absolute core of the solar system - the Sun.

The sun in the picture hangs alone in the deep universe, emitting light and heat.

And around it is a cosmic background color.

It looked empty.

It was not until the perspective was continuously expanded that Mercury, Venus, Earth, Jupiter, Saturn and other celestial bodies in the solar system appeared around the sun.

But in front of the giant sun, it seems almost negligible.

Overall it seems quite lonely.

【This is our sun, the only star in the solar system. 】

[But we know that there are a lot of stars in the entire universe, and there are more than 4000 billion stars in the Milky Way alone.]

[And stars are generally very far away from us.]

[It is common to hear a star that is tens of thousands of light years away from the sun.]

【So are there other stars around the sun? 】

[In fact, from our human perspective, there are no stars near the solar system. ]

[After all, humans are currently out of reach of even one light year. ]

[But from a macroscopic perspective of the universe, there are not only stars around the solar system, but it is even quite lively. ]

【There are many stars. 】

[Today we will start from the solar system and see which stars are our neighbors near the solar system. ]

【Maybe one day it will be like a movie. 】

[We are going to wander with the Earth and move to other stars! ]

[First understand the situation of the surrounding stars, which can be regarded as a preliminary visit and a way out. 】

【To understand the star of the sun. 】

【First, we need to figure out where the sun is. 】

[The location of the solar system is in the suburbs of the Milky Way. ]

[The exact locations are the Milky Way, the Orion Arm, the Gould Belt, the Local Bubble, the Local Interstellar Cloud, and the Solar System. ]

[The upper-level cosmic structure of the solar system is called the Local Interstellar Cloud, which has a diameter of about 30 light years. ]

[In addition to the sun, there are many other stars in this interstellar cloud. ]

[Using the example of humans, the other stars in this interstellar cloud are equivalent to living in the same community as our sun. ]

【They are neighbors in the same community. 】

[And the nearest stars in this interstellar cloud can be called neighbors. ]

[The star closest to the sun is naturally Proxima Centauri. ]

[This can be seen from its name. ]

[Proxima Centauri belongs to the Alpha Centauri-3 star system, which includes Alpha Centauri A, Alpha Centauri B, and Proxima Centauri.]

When the sky screen was played to this point, the ancient people were still watching attentively.
But the barrage couldn't help but burst into a small wave.

Three-Body, huh?

"By the way, when will the Trisolaran fleet set out? I can't wait."

"The Three-Body Problem is so bad that it's a gift for nothing."

"We humans are preparing to move to Proxima Centauri at the end of the world, but the Trisolarans are preparing to move from Proxima Centauri. Will we run into each other on the way?"

"The Three-Body Man: Silly Children, Don't Move to Proxima Centauri, It's Hell!"

The sky continues.

[Among these three stars, the closest to the sun is Proxima Centauri, which is only 4.2 light-years away from us.]

[Proxima Centauri is a red dwarf star, and its volume appears to be only slightly larger than Jupiter, about 1.5 times that of Jupiter.]

[But its mass is 150 times that of Jupiter, which is equivalent to 1/8 of the sun. ]

[The surface temperature is about 2770 degrees, less than half of the sun. ]

[And its luminosity is only 0.2% of the sun, which makes it very dim.] [So even though Proxima Centauri is the closest star to the solar system, it is still impossible to observe it directly with the naked eye.]

[In this star system, besides the most famous Proxima Centauri, there are Alpha Centauri A and Alpha Centauri B, which are about 4.37 light-years away from the sun. ]

[Star A is a yellow dwarf star with a mass about 1.1 times that of the Sun and a diameter 1.7 times that of the Sun.]

[Star b is an orange dwarf with a mass 0.9 times that of the sun. ]

[These two stars can be observed with the naked eye, but the distance between the two stars is very close, only 10 to 35 astronomical units. ]

[For comparison within the solar system, it is the distance from Saturn to the sun. ]

[Because the two stars are so close, when we humans observe them from Earth with our naked eyes, they feel like one star.]

[But in fact they are two stars, and they revolve around each other around a common center of mass.]

【It completes one revolution approximately every 80 years. 】

[These three stars form a three-star system that moves in relation to each other, and became the inspiration for the novel The Three-Body Problem.]

【Therefore, it has attracted a lot of discussion on the Internet. 】

[After them, the second closest star system to the sun is Barnard's Star. ]

【Its distance from the sun is 5.96 light years. 】

[Barnard's Star is also invisible to the naked eye because it is actually too small, with a mass and diameter less than 1/5 of the sun. ]

【And this star is moving towards the sun. 】

[Scientists estimate that in 1 years, Barnard's Star will be only 3.75 light years away from the solar system.]

[It will also become the closest neighbor to the solar system by then. ]

[Farther away is Wolf 359, which is 7.78 light-years from the Sun.]

[The diameter is about 1/6 of the sun, and the mass is less than 10% of the sun. ]

【Surface temperature 2500 degrees. 】

[Also because it is actually too small, it cannot be seen by the naked eye. 】

[Ranked fourth is Lalande 21185, a red dwarf star 8.29 light-years away from the sun. ]

[Among red dwarf stars, he is considered relatively large. ]

[Both its mass and diameter are more than 40% of the Sun. ]

【Surface temperature is about 3500 degrees. 】

[Lalande is the brightest red dwarf star in the entire northern sky, but it is still invisible to the naked eye.]

【And ranked fifth. 】

【It is the brightest star in the night sky. 】

【The famous Sirius! 】

【Sirius is very bright.】

[It is the brightest star in the night sky. Even at noon, Sirius can be observed with a telescope due to its apparent magnitude of -1.45.]

[Sirius is very close to us, only about 8.6 light years away. ]

[Although it has always been called Sirius, in fact Sirius is a binary star system. ]

[The main star is called Sirius A, and the companion star is Sirius B. ]

[Sirius b is a white dwarf, its volume is even about the same size as the Earth, but its mass is slightly larger than the Sun! ]

【It is one of the most massive white dwarfs known to date. 】

[Imagine compressing the sun to the same size as the earth, how high would the density of this planet be? ]

[Sirius b is such a planet. ]

[Its mass is more than 33 times that of the Earth, and its surface temperature is about 2500 degrees.]

[Sirius b is currently a white dwarf and has entered the final stage of its life. ]

[It will eventually evolve into a black dwarf after a long time. ]

[Sirius A, the main star of Sirius, is even more important. 】

[It is a blue dwarf star, with a mass 1.78 times that of the Sun, a brightness 1 times that of Sirius b, and more than 27 times that of the Sun! ]

[It can be said to be very bright. ]

[This is why Sirius is the brightest star observable to the naked eye, second only to the sun.] (End of this chapter)