The development of science and technology has continuously improved the ability of human beings to understand the world, and human beings are becoming more and more aware of the world they are in, and they know more and more things.

In ancient times, when humans painted a map of their own lives, they often used mountains, rivers, etc. as reference objects. The maps drawn were at most hundreds of miles within their own lives, and they were often not clear and accurate.

With the further development of science and technology, humans entered feudal society. During this period, humans had dedicated people to study the world they lived in, such as the astrological officials in ancient China. When drawing maps of their own countries, they would refer to the sun, moon, stars, etc. The maps drawn were very vast and the relative accuracy was not satisfactory.

In modern times, with the rise of modern scientific ideas, the development of the Western Enlightenment, and the rise of humanities, human beings have had a relatively correct understanding of the time they live for the first time, knowing that they live on a huge ball, and the rise of the great voyage, the world map is gradually becoming clear.

In the 20th century, with the development of aerospace technology, humans began to view the world they live in from space, and they recognized their world very intuitively and clearly, drew a world map with extremely high accuracy, and even had enough understanding of the galaxy they were in, able to draw a map of the galaxy.

Later, with the development of imperial science and technology, humans officially entered the universe and galloped across the entire Milky Way. In the river galaxy, how to determine their position and distance, and how to accurately draw the star map of the entire Milky Way, scientists used pulsars very cleverly to accurately position themselves so that they would not be lost in the universe.

Now that the empire has reached level 6, it has become a real cosmic civilization. To mix in the universe, how to draw a cluster of Virgo galaxies, the cluster of galaxies where the Milky Way is located, how to accurately measure the distance between rivers and so on, and many other problems have always troubled the empire's cosmic astronomers!

Astronomical scientists in the universe actually mastered a method that could measure the distance between river galaxies - Cepheid variable stars!

Cepheid variable stars are a type of variable stars. Its light change period (i.e., the time of the brightness change for one week) is proportional to its luminosity, so it can be used to measure the distance between the interstellar and intergalaxy. Most of these variable stars are F-type stars (medium-temperature hot stars); and when the light is very small, they are G-type stars (a star that is colder like the sun).

The typical star is the zodiac δ. In 1784, John Goodley discovered its photovoltaic phenomenon, and in 1912, Levitt of the Harvard Observatory discovered the period-photometric relationship of the above-mentioned Cepheid variable star.

Cepheus variable stars are a type of high-light periodic pulsating variable stars, that is, their brightness changes periodically with time. They are named because of the typical star zodiac δ (Chinese name Cepheus 1). Since the distance between clusters and galaxies can be determined based on the circular light relationship of Cepheus variable stars, Cepheus variable stars are known as the "measurement ruler".

The Cepheid variable star method can measure very long distances between rivers, so it can be obtained as the title of "Sky Measuring Ruler". However, in essence, this method is to study the spectrum you can receive from outside the distant river galaxy. At a distance of millions of light years between rivers, the light spreads over millions of years.

So what we see in the Milky Way now comes from Andromeda galaxy and triangular galaxies are all light emitted by millions of years. To study these lights to measure and infer the distance between rivers, it is not particularly accurate. What is more important is that we cannot know the precise location of the current long-distance river galaxy.

You should know that the Andromeda Galaxy, Milky Way, Triangle Galaxy and other rivers are running at high speed along an unknown trajectory at high speed every moment. The position of moving over millions of years will be very amazing, and the errors will be very huge.

Now the empire is going to expand the extra-river galaxy. Although the space transmission technology is great, if you can't even accurately position, the deviation of space transmission will be further widened, which will already be deviated. You can't even get the precise positioning of the river galaxy, and the deviation will be very amazing. Maybe a space transmission will be teleported to the sea of ​​death between the river galaxies, which will be miserable!

The Empire's cosmic astronomers continued to research and finally came up with two ways to cross distant distances and calculate the distant distances between rivers in real time, and at the same time accurately position the rivers, the deviation would be very small.

One is the spatial fluctuation method. The principle is to use the fluctuations generated by the squeezing of space by the super-large black hole in the core of the river to measure the distant distance between rivers, and the mass size of the black hole in the core of this sport can be measured based on the size, frequency, intensity, etc. of the wave, so that the size of the sport can be further inferred.

Because the size of a river galaxy is closely related to the core black hole. The core black hole has a large mass and strong gravity. The more interstellar dust matter it attracts, the wider the range of gravity influence, and the entire river galaxy will be more prosperous; on the contrary, the black-hearted black hole in a river galaxy has a small mass and weak gravity, and the less interstellar dust matter it attracts, the entire river galaxy will be more barren and much smaller.

Another method is to measure the distant distance between river galaxies and the situation of the river galaxies themselves according to the theory of space-time currents in the universe. According to the theory of space-time oceans in the universe, the entire universe is popularized by countless space-time currents. These space-time currents in the universe are large and small, connecting every river galaxy in the universe.

By measuring the size of the space-time currents connecting the universe of this river, the mass and range of the galaxy can be measured, and the current location of the galaxy can be measured based on the movement of the space-time currents!

Both methods are methods studied by astronomers of the Empire Universe. They are very accurate and can measure the distances of all rivers around the Milky Way in real time, and can also estimate the prosperity of this river.

Among the clusters of galaxies centered on the Andromeda Galaxy, Milky Way and Triangle Galaxy, the mass of Andromeda Galaxy ranks first. The mass of its core black hole is twice that of the Milky Way core black hole. The diameter of the entire Andromeda galaxy exceeds 220,000 light-years, and the diameter of the Milky Way is only 120,000 light-years!

As for the third-ranked Triangle galaxy, its core black hole has a mass of only half that of the Milky Way, so scientists can accurately calculate that its diameter is only about 60,000 light-years!

Furthermore, in terms of prosperity, the most intuitive thing that can reflect the prosperity and barrenness of a river is the number of stars in this river. The number of stars in the top Andromeda galaxy has more than 1 trillion, which is a very terrifying and huge number. The number of stars in the Milky Way has empire can give an accurate number. The Milky Way has 500 billion stars, while the Triangle galaxy has only about 80 billion stars, which is considered a very barren river!

Only by mastering the real-time location of these river galaxies can the space scientists of the empire use space transmission technology to transmit it to distant river galaxies very accurately. Otherwise, there will be errors in space transmission itself, and there will be errors in the distance of astronomical observation and measurement. Even if you master the space transmission technology, it is not easy to reach other river galaxies.

This is like using long-range missiles to attack. The missile itself produces some errors. If you cannot accurately know your location and the location of the target, then it is almost impossible for your missile to attack the target point very accurately!

The distance between rivers is too far, at least for now. It is often a long distance of millions of light years, and light needs to fly millions of light years. Coupled with the movement of the river itself, if the spectrum is used alone to calculate the distance between rivers and the precise position in real time, it is almost difficult to get a satisfactory result.

At least for empires that require space transmission, such results are unacceptable. Real-time precise locations must be obtained, and there must be sufficient understanding of this galaxy before it has been expanded.

What is the mass of this river galaxy, how large is the range, how many stellar systems are there, what is the structure of the river galaxy, the level of local civilization in the entire river galaxy, etc. Only by building on a sufficient understanding can the empire invade the entire river galaxy with confidence and boldness!

The triangular galaxy, which is 2.64 million light years away from the Milky Way, has a core black hole mass not very large. Taking the mass of the core black hole of the Milky Way as the standard, the mass of the core black hole of the triangle galaxy is only 0.56, while the mass of the black-hearted black hole of the Andromeda galaxy reaches 2.12!

Because the mass of the core black hole is relatively small, gravity and other aspects cannot be compared with the Milky Way and Andromeda galaxies. However, the triangle galaxy is still a huge river galaxy, which cannot be compared with the Milky Way attached satellite galaxy like the Great Magellanic System.

According to its structure, river galaxies can be roughly divided into four categories: vortex galaxies, spiral galaxies, rod-rotating galaxies and irregular galaxies. Of course, different classification methods will be classified differently. At present, the four categories generally recognized by imperial scientists are generally recognized by these four categories.

The Milky Way, the base camp of the Empire, is the rod-rot galaxy. The middle of the river galaxy is like a rod, hence the name; Andromeda Galaxy is a very typical vortex galaxy with a huge disc-shaped structure; and the triangular galaxy that the Empire is about to expedition is a very typical spiral galaxy!
Chapter completed!