In the universe, no matter can be stationary forever, and all celestial bodies cannot do without movement.
Our sun, every year, will move 7 billion kilometers in the universe with the eight planets .
Revolution of major planets in the solar system
What is this concept? The sun flew over Pluto in less than a year, without breathing in the middle.
And our probe flew from Earth to Pluto for a full 10 years before we arrived at Pluto.
If we humans have this speed, we have already left the solar system.
leap into the solar system
This is true for the sun, and the same is true for other stars. So why are the positions of the stars we see the same? Beidouxing pointed to the north as always.
Have you ever thought that maybe millions of years ago, the Big Dipper did not point to the north, and the stars we see are different from the ones we see.
The starry sky we see is different from what ancient apes saw
The revolution of the sun
The revolution is not the patent of these planets on Earth. As a star, the sun can also be revolving .
Compared with the revolution of planets in the solar system, The revolution of the sun itself is very magnificent. Its revolution speed exceeds that of any eight planets, and its period is also calculated in units of billions of years.
third cosmic speed calculated based on gravity 16.7 km/s indicates the minimum speed to leave the solar system. The human probe Voyager 1 must also achieve it through the gravitational acceleration of Jupiter .
However, the sun's revolution speed can easily reach 20 km/s .
The sun will also revolve
The longest Neptune among the planets, its year is 164.8 Earth years . Of course, if you want to be longer, you can count the removed Pluto, 1 Pluto year = 247.94 Earth years .
The year of the sun, that is, its revolution per week is about 2.7 earth years . That is to say, the last time the sun was here, it was still Permian , and dinosaurs did not appear.
At this revolution speed, the sun's movement distance in a year is 7 billion kilometers , which is equivalent to the distance from the sun to the Kuiper belt.
So the question is, we revolve around the sun, so who does the sun revolve around?
27 billion years ago Earth
In the center of galaxy where the sun is located, there is a huge black hole with a huge mass. It is called "gilant center black hole" in astronomy, also known as Sagittarius A*.
So although the Milky Way is beautiful and spectacular, its heart is really "black" , and it is very "black". has the mass of more than 24 million suns , and the sun is that rotates under its gravity.
In people's impression, black hole is a devouring monster. will absorb all matter close to it. Even light cannot escape.
One day our sun will be swallowed by this Sagittarius A*?
Sagittarius A*
The answer is yes, Sun is approaching the black hole of the galactic center, but before all this happened, the sun had already completed its entire lifespan and became an white dwarf star .
When it was finally swallowed, there was no solar system, only a tombstone of the sun existed.
Almost all stars in the Milky Way are controlled by the gravitational force of the galactic black hole, and they cannot escape the Milky Way , just as the Earth cannot escape from the solar system.
Since the positions of stars in the Milky Way are changing, why do we see the stars, , and the positions of the sky at night, do not change .
The medieval astrological map can still be used today.
Constellation diagram
The positions of stars
The stars in the Milky Way are revolving like the sun, and the annual moving distance of is billions of kilometers . Why has the positions of these stars not changed?
It is true that 7 billion kilometers is a big number , but putting this distance into space is really not worth mentioning .
This is like two ants crawling on a piece of paper . They crawled hard, but in the eyes of the people on the side, this distance cannot even get out of the edge of the paper.
These two ants are invasive species. Humans take planes to send them back to their hometown in South America. For the ants, it will never be able to climb back to South America from Asia.
Two tiny ants
Compared with analogy, the sun and other stars are these two ants, no matter how they move, they are within the range of a piece of paper. The earth is the universe for them.
So, it is not that the position of the stars remains unchanged, but that the change of is not considered much as compared to the universe, let alone the human eye to observe.
If you want to see the location changes with your naked eyes, you need to wait for dozens or millions of years , but can a person's lifespan patiently wait until that day?
is obviously impossible, so cannot observe the change in position for hundreds of years , so the medieval astrological map can also be used now.
A person's life span is limited
If you want to see the change in the position of a star, you may have to observe from 2 million years ago when humans were just born. At that time, maybe there were not as many constellations as today.
In addition, although stars are operating around the black hole in the center of Milky Way , these operations of are not messy . will maintain the corresponding position in in a short period of time.
Note that is the short time for the orbital period of a star. It is not a short time in the human sense. Hundreds and thousands of years are just a very short time for a star.
Millions For humans,
Also, the sun's orbital cycle is too long, about 270 million years. Not to mention humans, there are several species whose history can rival such a long time.
This is like humans can see all the moon phases of on the earth for a month. If you want to see the changes of other stars on the sun, you have to .27 billion years to see all the other astrological phases of .
To put it bluntly, Human life span is too short , the sun's motion distance is too short in the universe , and are all too short .
However, human wisdom is infinite and our lifespan cannot be observed, but can preview the changes in the next few millions or even hundreds of millions of years .
Astronomers can continuously observe the same star, write its motion data into the program, and simulates its future motion toward through a computer.
For example, humans simulated Beidou Star will become "North Tackle Star" in 100,000 years.
Similarly, using computer programs, you can simulate the Beidou Star 9.1 million years ago. At that time, the Tianshu Star in the Beidou Star was very far away from the second Tianxuan Star , and it is located diagonally above the fourth Tianquan Star. The shape of is not "dou" .
What is the Big Dipper now
However, astronomers found that some stars in the night sky are indeed dimmer than before .
In 2015, the Swedish National Observatory used a telescope to observe the direction of jackal , and took a photo. After comparing the photos at the same location in 2007, it was found that one star was missing.
This reminds people of the black hole swallowing . After all, the revolution of our sun occurs under the drive of the black hole.
stars disappear in the same area
Black holes of the Milky Way
Black holes are the form of supermassive stars after death. The Milky Way we are in has more than 100 billion stars , of course they are big and small.
Astronomers infer from stellar evolution models that there are more than 10 million black holes in the Milky Way, and it is possible that there are even hundreds of millions.
The mass of Sagittarius A* is not the largest among the black holes found so far. On the contrary, it still appears relatively small.
For example, the M87 black hole , which is 25 million light years away from our 5html, has a mass of 96.5 billion times that of the sun, and
, and our Milky Way has a diameter range of 9.2 million light years. It is impossible for only one black hole to exist.
M87 galaxy black hole
There is a conjecture that galaxy black hole is likely to have more than one galaxy black hole, but a group of black holes , Sagittarius A* is just one of them.
I believe many people are worried about one thing, that is, black holes swallow the solar system. This worry is actually not unreasonable.
Theoretically, the number of black holes in the Milky Way is more than 100 million, but The black holes discovered by humans so far are less than the fraction of this data.
black holes can also move, and their movement trajectory is not known at present. For example, our galactic black hole also has its own revolution.
even has wandering black holes in the universe, such as roaming black hole SDSSJ0927+2943, which is 600 million times that of the sun and drifts at a speed of more than 99 million kilometers per hour.
The process of shooting black holes
What will happen if they roam into the Milky Way? Scientists cannot predict accurately.
The oldest black hole in the universe ULas J1120 +0641, with an age of about 13.7 billion years old , it is considered to be the first black holes in the universe.
In short, black holes are far more complex than people think, and they are even divided into many types, such as rotating and non-rotating, charged and uncharged.
We still have little knowledge of black holes
In 2022, NASA released a recording, which is the sound of black holes swallowing nebula, because the nebula is composed of gas, and a thin medium is formed around the black hole, which can spread sound.
