"The North Star, the closest Cepheid variable star, is hundreds of light years away. However, the farther the star, the smaller it is. Using this method and through complex calculations, we finally calculated the approximate distances of various clusters containing variable stars.

The calculation process will be published in the journal Nature. The most cutting-edge developments in astronomy you have heard here. Before my speech, the astronomy community did not have the exact size data of the Milky Way. With the great trick of Cepheid variable stars, we can measure it with certainty.

We can even aim the telescope at globular clusters that are very different from the adjacent astronomical environment and find that they are very dense. If the earth appears in globular clusters, the shining of stars alone can turn the night into as bright as day.

And we can say with certainty that these strange star clusters are less than all the previous astronomical scales of less than 10,000 light-years. There are about 100 globular star clusters observed in the Milky Way, and there may be almost a similar number that has not been seen. We are about 20,000 to 200,000 light-years away.

We finally expanded the scale to 200,000 light-years. And we were able to reduce the distance of a large number of stars' self-propelled process into a picture that rotated around the center of the Milky Way. We used a computer to track the self-propelled millions of stars, and this imagination was born."

For the first time, humans "watched" the Milky Way from the vertical angle of the disc of the Milky Way. The big screen on the podium gradually flashed millions of stars one by one, shiningly showing the original appearance of the magnificent Milky Way.

Even the people watching the fun felt very fun, and astronomers were even more intoxicated. This was the first time they saw astronomy knowledge that could be used in front of ordinary people.

The Milky Way also had a beautiful spiral arm for the first time. Our solar system was on one of the spiral arms, not as people wished to believe in the Milky Way, but at the edge of the Milky Way.

Tangning made up the stars outside the tracking to make the Milky Way more perfect, and pointed out the specific location of the solar system, saying: "Don't think it's a good thing to be in the center. If so, why don't we live on the sun? Why don't we live in the center of the earth? Sometimes, the edges are better.

Just like the edge where the warm current and cold current intersect in the ocean, the waves are surging, bringing a large amount of nutrients to the sea surface. Life there is the most abundant, and the beauty of the edge is indescribable. The center of the Milky Way... Haha, I guess there is a huge gravity there, and even light cannot be brought in and out. Some lives will be torn into elementary particles under such terrifying gravity."

This last sentence was like a knife slashing people's hearts, causing a stir and whisper.

Listen to Tangning and telling you about this number, you can understand what terrifying gravity is: "We calculate based on the speed of the rotation of the Milky Way, the mass of the galaxy center, which accounts for most of the mass of the Milky Way, is far greater than 100 billion times the mass of the sun (there is a scream here), and then it is estimated that there are about 200 billion to 300 billion stars in the Milky Way, which is the first to estimate this number of w. Herschel's 100 million. (There is a surprise here)

Our Milky Way has a true diameter of about 100,000 light-years, like a disc. The thickness of the plate is 20,000 light-years at the center. Our position is about two-thirds of the center of the galaxy to the edge. It is also fine if we understand it as the golden division line. The thickness here is about 3,000 light-years.

Our Milky Way has two small neighbors, celestial bodies of the same galaxy as the Milky Way, one is the Little Magellanic Cloud and the other is the Big Magellanic Cloud. The Big Magellanic Cloud is 150,000 light-years away from us, and the Little Magellanic Cloud is 170,000 light-years away from us.

The Little Magellanic Cloud has extraordinary significance for astronomy because it has a total of 25 Cepheid variable stars, and is so far away from us that the distance between Cepheid variable stars is no longer important, so it forms a very regular brightness, allowing us to draw the periodic curve of the variable stars and become the basis for the comparison of interstellar coordinates.

The sages of the astronomy once speculated that some dim star spots might be made up of stars that are far away, but until we take action, the best telescopes cannot see its internal structure, only knowing that a star with extremely weak light will occasionally appear there.

I personally speculate that it was the last big burst of energy during the evolution of stars, and the erupted energy could illuminate the entire galaxy. That is to say, if such a big burst star comes from our Milky Way, its energy is equivalent to the sum of the energy of the stars in the entire Milky Way.

However, this theory is not important, because we have made the largest optical telescope, reaching 200 inches, and finally turned the conjecture of the ancestors into a real observation, which is famous inside the Andromeda nebula that often explodes in superstars."

The attendees of the UN General Assembly were fortunate to see a galaxy far away from the Milky Way on this occasion when they unexpectedly changed from a political conference to a scientific conference. They also have Cepheid variable stars, thus obtaining accurate distance data of 2.5 million light-years.

"Is this the farthest? Of course not. There are many distant galaxies similar to Andromeda nebula, which are farther away than Andromeda. So far, we have corresponded the scale of the universe to the age of the earth proved by geological evidence. The farthest galaxies have been traveling in the vast space for billions of years when they were seen by our telescopes.

Just think about the gorgeous starry sky we witnessed as a picture 2 billion years ago, a great respect for the universe and a sigh of tiny humanity will naturally arise in our hearts.

These 2 billion years are not the largest age of our universe, and we will have more powerful tools in the future. As we all know, the wavelength of light is easy to encounter obstacles, while the wavelength of electromagnetic waves can bypass obstacles. We are at the edge of the Milky Way, and logically speaking, when we look at the high density of the Milky Way, we can see much richer stars.

But the fact is that no matter where we look at the starry sky, the density of the starry sky is almost the same. So our former astronomers would think that our solar system is in the center of the Milky Way. In fact, this is because the density of the galaxy center is high and the density of gas and dust is also high, blocking a large amount of starlight.

There are often many coincidental things in nature that make us misjudgment. For example, the size of the moon looks similar to the size of the sun. It is a coincidence that the moon can just block the sun when it can form a perfect solar eclipse. That's because the sun is large, the farther away from us, and the moon is small in mass, so it can be very close to us.

The two parameters work together to produce a coincidence of solar eclipse that is so coincidental that the moon is not rotating. Moreover, the moon does not seem to be rotating, and the spots on it are almost motionless. This made our ancestors think that the moon does not rotate. In fact, this is the phenomenon of tidal locking.

The moon's rotation is just synchronized with the earth. One side of the moon always faces the earth and the other side always faces the earth. These coincidences just conform to the principles of physics.

To make our field of vision pass through annoying gas dust, we also made huge, radio telescopes that receive electromagnetic waves, and this time, we see farther and more."

The farthest viewed directly by an optical telescope is a million-dollar light-year meter, while the image synthesized by the radio telescope is a dark void that the optical telescope cannot see at all, which is equivalent to a picture of billions of light-years away.

At this scale, people are already numb. It seems that billions of light years are not as shocking as Galileo's first sight of the Great Galaxy, nor as shocking as Cepheid's variable star as surely the Andromeda nebula is 2.5 million light years away.

"I have noticed that everyone seems to have no interest in things that are billions of light years away. Yes, imagine that a prince and princess are married and live happily together in such a distant place. We want to visit this young couple, but when we arrive at the speed of light, billions of years have passed! Is this interesting?"

A knowing laughter rang out in the audience, and everyone thought the story of a galaxy that was too far away was really ridiculous.

"Radio telescopes tell us a deeper truth. In fact, the Andromeda nebula, which was originally thought to be incredibly far away and Kant called the "Cosmic Island", was only a close neighbor of our Milky Way. It is one of the galaxies that make up the "Cluster of the Galaxy" where our Milky Way is located.

Such a casual neighbor is larger than our Milky Way and has more stars than our Milky Way. Our galaxy cluster is only part of a large number of galaxy clusters, which also form a larger organizational supercluster with other galaxy clusters.

In the future, we may also discover super-super galaxy clusters. The universe is like an infinitely extended space. Whether it is endless or not, hundreds of millions of distances make us sigh.

Unfortunately, so far, the upper limit of the universe's speed is the speed of light. Not to mention it too far, our most recent 4.3 light-year Centauri Alpha is enough to let us walk for a while. It is very difficult to approach the speed of light, and we can imagine that with great engineering and scientific efforts, we can fly at one-tenth of the speed of light.

This is already very difficult. So it takes about a hundred years to fight back and forth from the nearest star. Based on the four-year government, it takes 25 governments to complete a scientific trial. For a government and a generation of people, this is such a difficult decision.

We here remind everyone that the distance is so slim. The inspiration for us is that it is more reliable to manage a one-point land that is within reach of our own. If we measure it by rice, it is close to the power of 10 to the power of 13.

The number of cells in our adult humans is about 10 to the power of 14. We ourselves are like a cosmic space. The cells of bacteria are much smaller than those of human cells. They exist in our small universe at a total of 10 times the total number of human cells.

Since the universe is so vast that it can only be viewed from afar and not played with, why don’t we place the greatest hope of human beings in our own small universe? Everyone has their own small universe and their own space. Moreover, the scale and grandeur of this small universe are no less than that of the large universe.

Human beings have endless boundaries and the development prospects of civilization are promising. Religion tells you that you either go to heaven to find bliss or restrain your own. Our scientific school reveals that bliss and richness can be discovered in infinitely small directions.

Today, we will also discuss a question related to the unity of physics and philosophy, which is also a question that Newton couldn't figure out why celestial bodies are so far apart, but gravity still seems to reach them instantly, allowing celestial bodies with mass to attract each other?

Our curiosity may be greater than Newton, because our radio telescopes have revealed a more magnificent picture that maintains gravitational forces between superclusters can actually exist across millions of light years. What is the mystery of them being so awesome?
Chapter completed!