I believe everyone is no stranger to the myth of "Houyi shooting the sun". It is said that there were 10 suns in the ancient sky, which scorched the earth and made people miserable. At this moment, a young man who shot at the sun appeared in the crowd. He is Hou Yi. Hou Yi took a bow and shot down nine suns in succession, leaving only one sun to shine on the earth. Although the story of Houyi shooting the sun doesn't sound true, there is indeed a system composed of many stars in the universe, and last year, a study found that there may be a second "sun" in the solar system.

Abraham Loeb, an astrophysicist from the Harvard-Smithsonian Center for Astrophysics, and his team published a research paper in the Journal of Astrophysics, saying that there were two stars in the solar system in the past. In other words, the solar system used to be a binary star system, and then something happened. A star left the solar system, leaving only the sun to persist until now. So what evidence is there that there are two stars in the solar system? Where is the other "sun" in the solar system?

According to 1: Multi-star systems are more common in the universe.

Before this research, scientists found that most star systems have many stars through long-term observation of star systems around the solar system, which is called multi-star system. Take the nearest neighboring galaxy to the solar system as an example. There are two larger stars in this galaxy, namely Star A and Star B, which revolve around each other. There is also a star C around the stars A and B, so they form a triad system.

In astronomy, a star system with two stars is called a "connected star system". In a stable satellite-connected system, the stars move in elliptical orbits with the center of mass as the focus. At present, humans have clearly detected Sirius, Cygnus X- 1 and Nanhesan. A system with three or more stars is called a "multi-star system", and different star systems can be named according to their numbers. For example, a system with three stars is called a Trinary star system or a three-body system.

Compared with the connected star system, the inside of the connected star system is more complicated, because the dynamic systems of multiple celestial bodies may cause chaotic behavior, so the stability of the connected star system is often weaker than that of the connected star system, and the stable stars of the connected star system are also weaker than that of the single star system. Astronomers have found through observation that more than 70% of the star systems in the Milky Way are multi-star systems, which makes the system composed of them attract a lot of substances.

Therefore, scientists have long doubted whether the solar system was once a star system, because there are not only eight planets in the solar system, but also an asteroid belt and a Kuiper belt at the edge of the solar system. Can the accumulation of so many substances be achieved by the sun's own ability? This question is still in doubt.

Basis 2: The existence of Oort Cloud

Oort cloud refers to the spherical cloud around the solar system, and there are many inactive comets at this level. There is a clear difference between the Kuiper Belt and the Oort Cloud. The former is a plane area where comets, meteorites and other small celestial bodies are distributed, and the latter is a space area, which not only surrounds the Kuiper Belt, but also includes the upper and lower space of the solar system. The first person to put forward the concept of "Oort Cloud" was Estonian astronomer Ernst Aupic, who proposed in 1932 that comets are clouds from the outer edge of the solar system.

However, the existence of Oort Cloud has aroused the suspicion of scientists, because there are too many substances in this area. According to theoretical calculation, it is impossible to attract so many substances by the sun alone. Therefore, scientists believe that there is the possibility of a second "sun" in the solar system. In order to test this hypothesis theoretically, Abraham and his colleagues built a simulation model by computer, and found a completely different situation through simulation experiments.

If there is another star in the solar system, it and the sun will form an invisible gravitational network, which can attract anything near the solar system. In the early days of the formation of the solar system, these two stars accumulated "original capital" in this way, and then used these "capitals" to build an outer protective structure. There are also views that the existence of Oort cloud may indeed be related to the second star.

But it is not the sun and another star that are attracted by gravity, but a large number of fragments appear after the disintegration of the second star, which accumulate in the outer layer of the solar system, thus forming the Oort cloud. Either way, it is related to two stars.

Basis 3: There may be a ninth planet on the edge of the solar system.

When NASA's Cassini probe detected Saturn, scientists speculated that there might be the ninth planet on the edge of the solar system based on Saturn's detection data. It is not Pluto, but a real planet. Some time ago, Jacques laskar, a scientist from the Paris Observatory, published a research paper in Astronomy and Physics, which pointed out that Laskar and his team had calculated the trajectory of the ninth planet.

Laska said that the trajectory of the ninth planet is unusual, which is why humans have not found it for a long time. The hidden planet is in an elliptical elongated orbit, which has a huge angle with the ecliptic plane. In addition, it moves in the opposite direction to other planets in the solar system, which leads to the ninth planet being in the opposite space position to the eighth planet most of the time.

Laska said that his team has reduced the workload of discovering the ninth planet by about half, and the rest of the work depends on the joint efforts of other scientists. Two months after Laska published his scientific research results, two other astronomers, Constantine and Brown, predicted that the volume of the ninth planet might be about 10 times that of the earth. If we want to verify the existence of the ninth planet in the future, we need to build a huge telescope and spend years or even decades observing it.

So what is the relationship between the prediction of the ninth planet in the solar system and the prediction of the second star? If there is a second star in the solar system, the possibility of the existence of the ninth planet will be further improved. Before the prediction of the ninth planet was put forward, Pluto was the outermost celestial body in the solar system, smaller than the moon, indicating that the solar gravity in that area was very limited. How can we bind a planet 10 times larger than the earth?

So the existence of the second star in the solar system is one of the prerequisites for the existence of the ninth planet. If this precondition is not established, the possibility of the existence of the ninth planet will be greatly reduced.

If the second "sun" did exist, where did it go now?

Then the question is, if there is a second "sun" in the solar system, where did this "sun" go? Shiraz, a scientist who supports this hypothesis, said that billions of years ago, the solar system was still a binary star system, and then a star larger than two stars passed through the solar system, causing the sun to be "dug away" and the second sun to be captured by a massive star. Moreover, Silas believes that the solar system was "dug away" after the formation of the Oort cloud.

Another hypothesis points out that the second star in the solar system is perturbed by gravity at the center of the Milky Way galaxy, which leads it to not only break away from the binary system composed of the sun, but also disintegrate in the process of breaking away. The partially disintegrated fragments are scattered between Mars and Jupiter, forming an asteroid belt. Another part of the debris reaches the Oort cloud area under the traction of gravity, which leads to a great increase in the material density in this area.

There are two suns in the sky. How did this happen?

To sum up, there may have been another star in the solar system in the past, and this hypothesis needs more scientific evidence to prove. A few years ago, the phenomenon of "two suns" appeared in the sky in the northeast of China. What happened? The first thing to make sure is that there is only one sun in the solar system at present, so one of the two suns appearing in the sky must be true and the other must be false. Later, experts from the Meteorological Bureau explained this phenomenon, which is a "magic day" phenomenon.

The essence of magic sun phenomenon is the optical phenomenon of the atmosphere. There are a lot of translucent thin clouds in the sky, and there are many hexagonal ice crystals in the thin clouds. If arranged neatly together, they will refract sunlight. These tiny ice crystals are arranged like prisms, and will be refracted when sunlight hits the ice crystal array from top to bottom. And we look at the sun from the perspective of looking up, so we will find that there are two suns in the sky, the one with the highest brightness is true, and the one with the darkest brightness is a reflection phenomenon.

According to meteorologists, the phenomenon of magic sun usually appears between 5: 30 and 6: 00 in the morning, but it can't be seen everywhere, which is related to the air condition and latitude position. Magic sun usually doesn't last long, so it's lucky to see this phenomenon.