A red dwarf is fast approaching the solar system, leaving us 1.5 million years to go

With the help of science and technology, after walking out of the earth, we see a vast universe. At the same time, we also find that the celestial bodies are not stationary, but moving very regularly. In the early days, scientists found that the earth revolved around the sun while it was rotating. The speed of the revolution was about 30 kilometers per second. One revolution was a year.

It is the earth’s rotation and revolution that has day and night, and changes all the year round. At this time, people think that the sun is motionless, and the eight planets move around it. The reason why people think that the sun is motionless is that scientists have not yet observed the stars outside the solar system and do not know that there is still more vast space outside the solar system.

Later, scientists observed extragalactic objects and learned that there is a galaxy outside the solar system, and there is a vaster sky beyond the galaxy. After recognizing the existence of the Milky way, we observed that stars are also in motion, it is not stationary. In the galaxy, the sun revolves around the massive object in the center of the galaxy, reaching 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, most of which move around the silver center with the sun. But the speed of these stars is different, some faster than the sun, some lower than the sun, and some similar to the sun. Because hundreds of billions of stars move around the silver center at different speeds and their orbits are not circular, there will be relative velocities between stars and stars.

The rotation of stars is not completely synchronous, so as time goes on, they may be very close, or even collide. The mass of stars is very large, and stars are basically not lone Rangers. There are always stellar systems around them, and there are a number of planets and small bodies around them.

When a star moves around the center of the galaxy, it will also drive the whole galaxy around the center of the galaxy. If the distance between two stars keeps getting closer, even if they collide, it will be very unfavorable for the stability of the whole stellar system, and may even directly lead to the destruction of a galaxy. If there are living planets in this stellar 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, Gaia satellite was launched. The observation equipment carried by Gaia has the accuracy and efficiency never before. Its main observation target is the stars in the galaxy.

After the launch of Gaia satellite, it provides us with a lot of star data, especially the orbit of about 300000 stars around the sun. By calculating and analyzing the orbits of these stars, we can find out which stars will threaten us.

Through the research and analysis of star data, it is found that the future of the solar system is not optimistic. There are as many as 300000 stars around the solar system, and many of them will slowly approach the sun in the process of continuous movement. In particular, a red dwarf named “Gliese 710” is approaching the solar system in its orbit. According to the current observation and analysis, it will reach the position of the Oort cloud in 1.5 million years.


Gliese 710 is located in the direction of the constellation Serpens, only 63 light-years away from us, with a diameter of about 800000 km and a mass about half the mass of the sun. According to its current orbit, it will be only 1 light-year away from the sun in 1.5 million years at most, which happens to be in the Oort cloud.

I believe many friends have heard of the Oort cloud. 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 solar system was bounded by the top of the heliosphere, that is, out of the Kuiper belt, out of the solar system. By this standard, Voyager 1 and Voyager 2 are already out of the solar system.

But later, scientists observed and found the Oort cloud outside the solar system, redefined the scope of the solar system, and believed that only when we go out of the Oort cloud can we really go out of the solar system and enter the extrasolar interstellar space. By this standard, Voyager is still within the solar system, and it will take at least 10000 years to get out.


Although Gliese 710 is approaching the solar system, it will not collide with the sun. Even so, after 1.5 million years, the earth will still face a big challenge, because there are countless celestial bodies inside the Oort cloud.

The mass of the sun accounts for 99.86% of the total mass of the solar system. It can firmly bind the eight planets and a large number of inner Galaxy celestial bodies with absolute mass advantage, and will not be affected by the gravity of red dwarfs. However, with the increase of distance, the influence of the sun’s gravity will become weaker and weaker, especially outside the heliosphere, the influence of the solar wind will not exist.

When it comes to the Oort cloud, the influence of the sun’s gravity on the celestial bodies is very weak. Originally, for a long time, the celestial bodies in the Oort cloud can basically maintain a stable state, which will not have a great impact on the galaxies in the sun. But when the red dwarf Gliese 710 approaches the Oort cloud, it’s a different story.


Gliese 710 has half the mass of the sun, and its gravity is naturally not small. Although its gravity will not affect the galaxies in the sun, it will have a great impact on the Oort cloud. Its arrival will completely disturb the Oort cloud and make the small objects, such as asteroids and comets, seriously deviate from their orbits.

There are a large number of comets inside the Oort cloud. In the early solar system, about 3.8-4.1 billion years ago, the inner solar system experienced a “post heavy bombing period”. The reason is that the abnormal movements of Jupiter and other giant planets caused the asteroids and comets in the asteroid belt and the Kuiper belt to break into the inner solar system on a large scale.

In these dark years, both the moon and the earth suffered violent impacts. The dense craters on the earth were formed by the impact of a large number of small celestial bodies at this time. Of course, the earth was not spared. It also suffered a large number of small planets and comets that were more serious than the moon. The reason why we see these traces now is that the ecological environment has erased everything.


We all know that 65 million years ago, only an asteroid with a diameter of about 10 kilometers hit the earth, which ushered in the fifth mass extinction and the end of the era of dinosaurs, which dominated the earth for 160 million years. And the impact intensity of this kind of impact can not be compared with the impact of “post heavy bombing period”.

In the Oort cloud, the number of comets far exceeds that in the asteroid belt and the Kuiper belt. If their orbits deviate and a large number of comets rush to the inner galaxies, the earth will be in great trouble. At that time, the impact on the earth will be several orders of magnitude higher than the “post bombing period”. In such an impact, not to mention the life of the earth, even if the planet earth can exist is also an unknown.

Fortunately, it will take another 1.5 million years for this red dwarf to be close to the solar system, which provides a long time for human development. As long as human beings can continue to develop science and technology, 1.5 million years will be enough time for human beings to become an interstellar civilization. Only with the strength of interstellar civilization can we solve the earth’s crisis. Even if we can’t guarantee the safety of the earth, human beings can choose to leave the solar system and live in other galaxies.


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