The Secret of Street View and Starry Sky

One sunny summer, my father took my brother and me to an empty football field in Beiwai. We look up at the stars and listen to our father telling stories in the sky.

At that time, there was no air pollution, and the stars were bright, like attending a grand dance. But the first question we met was: "Who is the star?" Father told us that the Big Dipper was the first thing to show us. Along the connecting direction of the two stars in front of the bucket, it is easy to find the "Polaris", which makes the axis of the celestial sphere rotate.

The relative position between the stars is fixed, and the figure they make up has been given a very vivid name by the ancients. What constellation are the stars that make up a certain figure called together? The Big Dipper is the constellation Ursa major, and the appearance of the bear needs the observer's "brain supplement". Don't we often name rocks by imagination when we travel?

However, the naming of constellations is more important, because it is the basis for watching the starry street view. Constellation 88 is the administrative division of the starry sky and the official "map" of the sky.

Father said that we can only see half the sky in the northern hemisphere. If you want to see the other half, you must go to countries in the southern hemisphere, such as Australia and South Africa.

The starry sky seen at different times is different, because the earth rotates from west to east, just like a "revolving restaurant" in space. The rotation of the stationary celestial sphere relative to the earth feels like rotating around the Polaris in the opposite direction, once a day.

The ancients didn't think so. They think that the earth is stationary and everything in the sky revolves around it. We are the center of the universe. The more ignorant we are, the more self-centered we are. Whenever knowledge expands into a new field, more unknown things will be discovered. Science begins with human observation of the starry sky.

In addition to rotation, the earth revolves around the sun. The ancients divided the trajectory left by the sun in the street view of celestial bodies into twelve parts, with an average of one part per month, and the constellation in each corresponding position was what everyone called personal horoscope. For example, on my birthday 222, I fell into Pisces. There is a problem with the time estimation marked in the above picture. I copied it online, too.

Your date of birth will always belong to one of the twelve constellations, or to be precise, one of the thirteen constellations. Because it has been more than 2000 years since the geocentric theory was founded, the earth is like a shaking top, and there are also "precession", and there are more Ophiuchus. But fortune tellers don't care about those scientists, and stories can impress believers more.

These twelve constellations are related to the date of birth, so they become the "stars" among the 88 constellations. Archaeologists may be able to decipher some historical secrets from these constellations. After all, those numbers must be closely related to human life at that time.

Well, we have a map of space travel, and we can clearly tell the story of the universe where it happened. So what types of characters are there in space stories?

Planets, stars, galaxies, clusters of galaxies ... This paper takes stars as the leading role and talks about the past lives of stars. Of course, the nearest star is the sun, which rises in the east and sets in the west. Who has really seen the earth go around the sun? Isn't the sun all around the earth? If the ancients crossed into today's society, they would be very unconvinced by the "heresy" of science. So intuition is very unreliable.

This second part is not a story told by dad. After all, he made me curious about the mysteries of the universe.

Speaking of stars, the stars in the sky mentioned above are actually stars, and they are themselves luminous bodies like the sun. But why do they shine? What kind of structure does a star have? What are the differences in the structure of stars? Are they eternal, or have their own life cycle?

A star is a fusion reactor. How do we know the operating mechanism of this distant star?

Space is limited, briefly speaking, through spectral analysis, the data of sunspots and solar wind on the sun, and based on various nuclear physical models known on the earth, a star model is established under various logical deductions such as self-consistency and coincidence. The best embodiment of the overall life evolution of the star is the above Z Ryan Roto.

Is a photo that amazing? It's really amazing that the basic situation of the evolution of all stars can be outlined only by luminosity and temperature.

There is a difference between luminosity and brightness, and the distance between the star and the observer has been deducted. It is more intuitive to understand by converting solar luminosity into relative value; Temperature reflects the strength of nuclear fusion against gravity; The star on the upper right has a low temperature, but it has such a high luminosity, which only shows that it is very large and has a very large surface area, so it is called a red giant. The stars in the lower left corner have high temperature and intense reaction, but their luminosity is very low, indicating that they are dense and have small surface area.

It is easier to understand that the main sequence star is located on the diagonal of the lower slope. 90% of the stars are located in this area. The higher the temperature, the higher the luminosity, and most of the life cycle is located in this area.

Seeing the evolution diagram above can deepen our understanding of Herodotus. Our sun is located in the central region of the main sequence star, and its life span is about 654.38+0 billion years. Nowadays, when people reach middle age, they will one day run out of nuclear fuel, become huge red giants and finally evolve into dense white dwarfs.

It seems that the upper right area of Herotto is the star's "nursing home" and then sent to the lower left area for "hospice care". It is normal for young and middle-aged stars to stick to the "main sequence star" area.

This paper introduces two kinds of charts in astronomy. Constellation graphics have become various "landmark buildings" in the sky. Herotto reveals the nature of stars and past lives. If the mass of the star exceeds 1.44 suns, the evolution above will produce neutron stars and even black holes. And this limit is called "Chandraseka limit". To be a strong man in the universe, one must reach the standard in quality. Is really "Yi Long gave birth to a dragon, a phoenix gave birth to a phoenix".