When human beings walked out of the earth with the help of science and technology, we saw a vast universe. At the same time, we also discovered that the celestial bodies were not stationary, but moved very regularly. In the early days, scientists discovered that the earth was revolving around the sun while it was rotating. The revolution speed is about 30 kilometers per second, and one revolution is a year.
It is the earth’s rotation and revolution that have day and night, and have changed throughout the year. At this time, people think that the sun is still and the eight planets are moving around it. The reason why people think that the sun is still is mainly because scientists have not yet observed the starry sky outside the system, and they don’t know that there is even more vast space outside the solar system. A vast space.
Later, scientists observed extra-solar celestial bodies and learned that there is also the Milky Way outside the solar system, and that there is even more vast starry sky outside the Milky Way. After recognizing the existence of the Milky Way, we observed that the star is also in motion, it is not stationary. In the Milky Way, the sun orbits the massive celestial body in the center of the Milky Way at a speed of 240 kilometers per second, which is 80 times the speed of the earth’s revolution.
In the Milky Way, there are 100-400 billion stars, and most of them move around the galactic center with the sun. It’s just that these stars move at different speeds, some are faster than the sun, some are lower than the sun, and some are similar to the sun. It is precisely because the speeds of hundreds of billions of stars moving around the galactic center are different, and the orbit is not a circle, so there will be relative velocities between stars and stars.
The revolutions of stars are not completely synchronized, so as time goes by, they may be very close or even collide. The masses of stars are very large, and stars are basically not alone. They often have stellar systems around them, with varying numbers of planets and small celestial bodies moving around them.
When a star moves around the galactic center, it will also drive the entire star system to move around the center of the Milky Way. If the distance between the two stars keeps getting closer or even collides, it will be very unfavorable for the stability of the entire star system, and it may even directly lead to the destruction of one galaxy. If there are living planets in this star system, the consequences will be more serious, and the living planets may also end.
So is it possible for the sun to be close to other stars in the future? On December 19, 2013, the “Gaia” satellite (Gaia) was launched into space. The observation equipment it carried had unprecedented precision and efficiency. Its main observation targets were the stars in the Milky Way.
After the “Gaia” satellite took off, it provided us with a large amount of stellar data, especially the orbits of about 300,000 stars around the sun, which is the focus of attention of scientists. By calculating and analyzing the orbits of these stars, we can get which stars pose a threat to us.
Through the research and analysis of stellar data by scientists, it is found that the future of the solar system is not optimistic. There are as many as 300,000 stars around the solar system, many of which will slowly approach the sun during continuous movement. Especially for a red dwarf named “Gliese 710”, its orbit is constantly approaching the solar system. According to current observations and analysis, it will reach the position of the Oort Cloud in 1.5 million years.
“Gliese 710” is located in the direction of Serpents, only 63 light-years away, about 800,000 kilometers in diameter, and about half the mass of the sun. According to its current orbit, it will travel to a position only 1 light-year away from the sun in 1.5 million years, and this position happens to be in the Oort Cloud.
Oort Cloud believes that many of my friends have heard of it. It is the outer region of the solar system with a thickness of one light-year. Before the Oort Cloud was observed, scientists believed that the range of the solar system was bounded by the top of the heliosphere, that is, out of the Kuiper belt and out of the solar system. By this standard, the current Voyager 1 and Voyager 2 have already flown out of the solar system.
However, scientists later discovered the Oort cloud in the periphery of the solar system, redefining the scope of the solar system, and believed that only walking out of the Oort cloud could be regarded as truly walking out of the solar system and entering the outer interstellar space. By this standard, the Voyager is still in the solar system range, and it will take at least 10,000 years to go out.
Although the “Gliese 710” red dwarf star is constantly approaching the solar system, it will not collide with the sun. Even so, 1.5 million years later, the earth will still face a big challenge because there are countless celestial bodies in the Oort Cloud.
The mass of the sun accounts for 99.86% of the mass of the entire solar system. It can firmly bind the eight planets and a large number of inner galaxy celestial bodies with absolute mass advantages, and will not be affected by the gravity of red dwarfs. However, as the distance increases, the sun’s gravitational force will become weaker and weaker. Especially outside the heliosphere, the influence of the solar wind basically does not exist.
Arriving in the Oort Cloud, the celestial bodies here are very weakly affected by the sun’s gravitational force. Originally, during the long years, the celestial bodies in the Oort Cloud can basically maintain a stable state, and will not produce a big impact on the galaxies in the sun. influences. But after the red dwarf “Gliese 710” approached the Oort Cloud, the situation was completely different.
The mass of “Gliese 710” is half that of the sun, and the gravitational force produced is naturally not small. Although its gravitational force will not affect the inner galaxy of the sun, it will have a very large impact on the Oort Cloud. Its arrival will completely disturb the Oort Cloud and cause the small celestial bodies, such as asteroids and comets, to deviate seriously. Own running track.
There are a large number of comets in the Oort Cloud. In the early solar system, between 3.8 billion and 4.1 billion years ago, the inner solar system had gone through a “post-heavy bombing period” due to the abnormal movements of giant planets such as Jupiter. As a result, asteroids and comets in the asteroid belt and the Kuiper belt intrude into the inner solar system on a large scale.
During this period of darkness, both the moon and the earth suffered violent impacts. The densely packed craters on the earth were formed by a large number of small celestial bodies at this time. Of course, the earth was not immune to it, and it suffered more severely than the moon. A large number of asteroids, comets hit. The reason why we see these traces now is mainly because the ecological environment has erased everything.
I believe everyone understands the threat to life caused by asteroid impacts. 65 million years ago, only an asteroid with a diameter of about 10 kilometers hit the earth, ushering in the fifth mass extinction of living things, and the era of dinosaurs that dominated the earth for 160 million years. End. The severity of such an impact is completely incomparable with the impact of the “post-heavy bombing period”.
The number of comets in the Oort Cloud far exceeds the asteroid belt and the Kuiper belt. If their orbits deviate and a large number of galaxies rush toward the inner galaxies, the earth will be in trouble. At that time, the impact that the earth will suffer will be several orders of magnitude higher than that of the “post-heavy bombing period.” Under such an impact, not to mention life on Earth, even if the planet Earth can exist is still unknown.
Fortunately, it will take 1.5 million years for the red dwarf star to approach the solar system, which provides a long time for human development. As long as mankind can continue to develop science and technology, 1.5 million years will be enough for mankind to become an interstellar civilization. Only with the strength of interstellar civilization, this earth’s crisis may be solved. Even if the earth’s safety cannot be solved, human beings can choose to leave the solar system and live in other galaxies.