Currently our universe is expanding, like a balloon that is being blown up, or like a bread being fermented in an oven, the galaxies in the universe are like coins attached to the surface of a balloon, or like raisins in bread ; Z1z
As the universe expands, the distance between galaxies will become farther and farther, and this relationship is that the farther away the galaxy is, the faster it will move away from us. The fact that the universe expanded
was obtained by Hubble in 1929 by observing the variable stars in the galaxy and the fact that the starlight is redshifted. In other words, our universe will expand into a larger space in the future, and the density of matter inside will become lower and lower;
When all galaxies gradually move away from us, their speed away from us will gradually exceed the light filament, which means Most of the galaxies we can see now will disappear from our field of vision.
But besides the expansion of the universe, another fact is also happening. That is, the universe is experiencing the merger of galaxies every moment, and our galaxy will experience the same fate in the future.
You may be confused, didn't you just say that the universe is expanding? The galaxies should be far away from each other, so why do galaxies merge in the universe?
The expansion of the universe is indeed true, and there is nothing wrong with galaxies far away, but don’t forget that matter in the universe also forms many large structures under the action of gravity.
For example, our solar system is a glimpse of the Milky Way. It is affected by the gravitational force of the Milky Way's center. The universe is expanding, but it will not break up the gravitational relationship between the solar system and the Milky Way;
, the same Milky Way and the Andromeda Galaxy, and the Triangulum Galaxy, Dozens of galaxies, such as the large , the small Magellanic Cloud, and the , also form a large family under the action of gravity, called the local group of galaxies.
In this group of galaxies, the Milky Way and Andromeda galaxies generally revolve around these two galaxies except for the central position. Among them, the Large and Small Magellanic Clouds are the satellite galaxies of the Milky Way and revolve around the Milky Way.
is obviously a gravitational structure like the local galaxy group, and the expansion of the universe cannot disassemble them. In the universe, it is these galaxies that have been bound to each other by gravity. In the future, they will merge into a larger elliptical galaxy.
Therefore, it is foreseeable that all galaxies in the local galaxy group will merge together in the future. It is estimated that the collision and fusion time between the Large and Small Magellanic Cloud and the Milky Way will be about 2 billion years, and the collision time between Andromeda and the Milky Way will be about 3.7 billion years. Later, the larger galaxy structure formed by these mergers will gradually sweep all the surrounding galaxies under the action of gravity.
will turn into a galaxy at that time, we can call it fairy-the Milky Way. As the universe expands, those galaxies that are not comfortable with gravity will gradually move away from us and disappear.
If there is still intelligent life on the earth at that time, all the celestial bodies they see in the sky and all the events that occur are within the range of the fairy-galactic galaxy;
if they look at the space outside their own galaxy, they will I found that there was nothing but darkness in the universe except my own galaxy. At that time they will come to the conclusion that, apart from the endless dark space, there is only one galaxy in the universe...
A paper recently published in the journal Nature Astronomy shows that the Large Magellanic Cloud galaxy has begun to affect the Milky Way. Movement and structure too.
Scientists discovered that the gas and dust on the edge of the Milky Way galaxy have been pulled by the powerful gravitational pull of the dark matter halo of the Large Magellanic Cloud orbiting it, causing its shape to change.
However, this discovery does not mean that the two galaxies are about to merge, but the Large Magellanic Cloud normally passes quickly from the position closest to the Milky Way (50Kpc, approximately 160,000 light years), creating a gravitational impression on the structure of the Milky Way.
And at such a long distance, it will not affect the overall structure of the Milky Way. After all, the mass of the Milky Way is 10 times greater than that of the Large Magellanic Cloud. Even if it collides and merges, the Large Magellanic Cloud must be the first to be disintegrated by the Milky Way’s powerful tidal gravity. Then was swallowed.
Large Magellanic Cloud is moving very fast when it passes the Milky Way, reaching 370 kilometers per second, and it is rapidly pulling and pulling the surrounding matter of the Milky Way.
caused the material around the Milky Way to be pulled out, torn or even twisted. By observing the gravitational interaction between the two galaxies, in the future we will be able to reconcile the gravitational forces of the Milky Way and the Large Magellanic Cloud and study the distribution of dark matter in the two galaxies.
So you must be more concerned about what happens when two galaxies merge? Will it affect the earth? The
galaxy is an island of stars in the universe. It contains hundreds of billions of stars, as well as stellar remnants such as black holes, neutron stars, and white dwarfs. The mass of gas and dust is larger. Therefore, the merger of galaxies is counted in the universe. It is the biggest super event.
What will happen when our Milky Way, the Large Magellanic Cloud and the Andromeda Galaxy merge in the future, we do not know now. But we can look at the merger events currently taking place in the universe, and we can see what will happen to our galaxy in the future!
The largest galaxy in the middle of the above picture is NGC 6872, which has a mass four times that of the Milky Way. The small galaxy on the lower right is IC 4970, which is about the size of the Milky Way. The merger of these two galaxies
was captured by the Gemini Telescope.
The position of the red arrow in the figure above can clearly see that the stars and gas at the spiral tail of the galaxy NGC 6872 have been pulled by gravity.
is like the Large Magellanic Cloud pulling the material on the edge of the Milky Way, but not so severely.
The above picture shows that there are very bright radio sources in the centers of the two galaxies. This is actually the black hole in the center of the galaxy. However, there are two radio sources in the center of the small galaxy IC 4970, indicating that there are two in the center of the galaxy. Black holes surrounding each other.
When the two galaxies merge in the future, the three black holes will also merge together to form a larger and more active black hole.
In addition to the above two merging galaxies, there are many merging galaxies in the universe. When two galaxies merge, the spiral structure of the galaxy will be destroyed due to the disturbance of gravitation, and the speed and position of the stars in the galaxy will change greatly.
In other words, if our Milky Way and other galaxies merge in the future, the constellations we see in the sky will be transformed very quickly.
And when two galaxies merge, the gas in the galaxy will quickly form new stars due to the disturbance of gravitational force. The star formation process of the entire galaxy will be very fast and intense, making the galaxy a starburst galaxy;
not only The speed of star formation is fast, and the speed of death will also increase. The merging speed of neutron stars and white dwarfs will also increase, causing the entire galaxy to explode very frequently and rapidly. When
arrives, our sky will look as bright as daytime;
The picture above is when the Milky Way and Andromeda Galaxy merge, we will see the scene on the earth, because the matter in the galaxy will be very chaotic when the collision occurs, and It will take a long time to regroup;
will have some wandering celestial bodies in the solar system, the probability of breaking into the solar system will increase significantly, these celestial bodies will affect the stability of the celestial bodies in the solar system, and of course pose a threat to the earth.
If there is no impact from foreign celestial bodies, high-frequency explosions and high-energy events in the galaxy will also cause the earth to suffer a very large radiation hazard, and life on the earth will definitely not be peaceful.
The most important thing is that a research team concluded in 2019 that the Large Magellanic Cloud will activate the central black hole of the Milky Way after it merges with the Milky Way in about 2 billion years, because the Large Magellanic Cloud also has a black hole with a mass of 2 million times the sun. ;Z1z
The merger of the two black holes, coupled with the reorganization of the galaxy's matter, will turn the merged black hole into a super black hole that often explodes with material jets.
makes the merged galaxy have oneAn active galactic nucleus or quasar. This is not a good thing for the earth.
Paper: Detection of the Milky Way reflex motion due to the Large Magellanic Cloud infall
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