The world's largest celestial body: UY Scuti, which can swallow 1.8 billion suns? nothing in front of it

Since human beings have their own wisdom, they have been looking up at the stars for tens of thousands of years!

While full of awe at the familiar and unfamiliar vast universe and vast sky, there are also countless curiosity. Even today, we have begun to escape the shackles of the earth, run to the moon and Mars, and begin to step into the trembling era of cosmic navigation!

But even so, there are still many secrets hidden in space, as vast as it, which makes us sometimes confused. Are our efforts really useful?

How big is this world?

The most apt description is that in 1990, when Voyager 1 flew 6 billion kilometers away from the earth, it looked back and took a close-up of its home planet, the earth!

Did not expect it!

This is already the highest-definition picture of Voyager 1, but the earth has turned into a small bright spot in the vast sea of ​​stars, which is very invisible. But as the astrophysicist and science writer Carl Sagan said with emotion: on this small point, there lives everyone you love, everyone you know, everyone you've heard of, everyone you've ever heard of. Existing on earth, and spending a lifetime, all happened in this small little...

Thousands of years of human civilization, tens of thousands of years of intelligent development, hundreds of years of evolution, and 3.8 billion years of the evolution of life on Earth all occurred in this 12,756-kilometer diameter, with a mass of 5.976 × 10^21 tons (59.76 trillion 100 million tons) on the little dots!

But at this time, Voyager 1 has still not flown out of the solar system we are familiar with. The earth is in the solar system, it is really nothing!

For example: compared to Jupiter, the eldest of the 8 planets, the Earth is only one of 1300 of its volume. Even in terms of mass, it is 318 times that of Earth.

If, comparing the earth and the sun, the volume of the sun is 1.3 million times that of the earth, this difference is like, if the earth is a small glass bead with a diameter of 1 cm, then the sun is about 1.1 meters high. Yoga ball. Of course, this analogy is not so appropriate, because in terms of mass, the mass of the sun is also 330,000 times that of the earth.

But when you look at the Milky Way, you will feel helplessly that the sun we are familiar with is not even a grain of sand. Moreover, in the star family, the current observation ability of human beings, the "sun" (star) with the largest volume is undoubtedly UY Scuti. How big is this largest star?

Its volume is about 1.8 billion times that of the sun. If the sun is still the yoga ball with a diameter of 1.1 meters, then it may be the circular meteorite with a diameter of 1900 meters.

That tiny earth is nothing in front of the largest "sun" with an actual diameter of about 2.374 billion kilometers! If you fill it with a small ball like the earth, you have to find at least 2340 trillion earths...

Of course, science requires rigor! From the point of view of mass, the largest star UY Scuti is only 7 to 10 times the mass of the sun, which is 2.31 to 3.3 million times the mass of the earth.

The most massive star ever observed by humans is R136a1, which is also a blue supergiant.

What is a blue supergiant?

This is the science of the long life of stars

Any star, like a human being, goes through gestation, birth, growth, middle age, aging and death.

The first stage: The nebula gas and dust in the universe continue to collide, converge and collapse, and then form protoplanets. You can understand this process as the placenta of stars.

The second stage: The mass of the dense gas in the inner core of the protoplanet is enough for hydrogen to ignite, and then fuse into helium continuously and stably. This stage also means that the main-sequence stars really fall to the ground and enter a growing star.

The third stage: when all the hydrogen of the star is burned, it begins to burn elements such as helium and carbon, which also means that it belongs to the star of the red giant.

The final stage: when all the hydrogen and helium in the star, all the fuel that can be burned, and any elements that can undergo fusion reactions, have been burned up. Under gravity, its core collapses and collapses, releasing enormous amounts of energy, which also means the death of stellar life.

Of course, this stage is also divided into different endings according to the quality. If the mass of the star is large enough, such as more than 8 times the mass of the sun, this stage is a supernova explosion. The remaining "corpses" are enough to have two results. Stars with masses 8 to 20 times the size of the sun will turn into neutron stars. More massive ones will become black holes.

If it is like our sun, after its old life-the red giant stage, after experiencing the death process of the planetary nebula, a white dwarf will be left behind, and then the residual heat will dissipate a completely non-luminous black dwarf.

The above analogy may not be so rigorous, but I hope to understand the development process of stars in the most popular way.

In addition, for most of the main sequence stars that are emitting dazzling light, human scientists will conduct a classification method called the MK system according to their spectral category (ie color), temperature, size and brightness. For example, according to the temperature of the stars, from high to low, O, B, A, F, G, K and M, 7 major grades and 9 small categories are arranged. (There is also a catchphrase or trick to remember these letters and order: Oh Be A Fine Girl Kiss Me)

At the same time, people can also use Roman numerals to distinguish its brightness, 0\I super or supergiant stars with the highest brightness, II, III and IV are suitable for bright giants, normal giants and subgiants in turn; category V is suitable for main sequence stars; Categories VI and VII apply to subdwarfs and white dwarfs.

Through this idea, smart astronomers have simplified such a stellar classification method to a relationship diagram. It was first proposed by the Danish astronomer Herzpron in 1911 and the American astronomer Russell in 1913. This is the origin of the famous Hertzsprung-Russel diagram (H-R diagram for short) in astronomy.

On the diagram, our familiar sun is marked as a main sequence star of G2V. On the HR diagram, the distribution area of ​​the stars is also clearly marked, and our sun is located on a diagonal line. Scientists call the star on this diagonal a main sequence star. When the main sequence star runs out of hydrogen, it begins to burn helium and expands to become a red giant.

R136a1, the most massive star that human observation can "see", is a highly luminous spectral star, also marked in the extreme upper left corner of the H-R diagram. Although R136a1 has a high mass, its temperature is "cool", about 56000K. Such stars are also defined as super blue giants.

This first star that has entered old age has a mass of about 265 to 310 times the sun, equivalent to the mass of tens of millions of Earths. In fact, it is not in the Milky Way that we are familiar with, but in the Large Magellanic Cloud. , about 163,000 light-years from Earth.

Of course, astronomers also have their own guesses about the formation of this most massive star: it may be formed by the merger of several massive stars, but for it, the time left for it is not much now. It will be the most powerful supernova and detonate the most brilliant light!

Then, go into its final ending - turn into a black hole!

This is also the largest celestial body in the world recognized by human beings.

Therefore, if such celestial bodies are also counted! No matter in terms of mass and volume, the largest single celestial object is not the two stars we have been describing above, but a black hole - the Ton618 black hole.

If we only count the core part of the quasar of this black hole.

The mass of this black hole is not only 66 billion times that of the sun, but it is also the largest single celestial body in the known mass. Compared with the black hole at the center of our galaxy, its mass is 15,500 times larger, which is about 1/1 of the total mass of our entire galaxy. 23, which is much larger than the total mass of some smaller galaxies.

For example, it is about 6.6 times the total mass of the Large Magellanic Cloud and more than 100,000 times the total mass of the Segre 2 galaxy. From this concept, you can probably imagine how huge this celestial body is!

Of course, don't worry too much, this behemoth is 10.4 billion light-years away from us.

Perhaps, many people will be curious, doesn't it mean that black holes are invisible? So how do people observe it, and how do they calculate its mass and volume?

However, following the current theoretical knowledge of black holes, ordinary black holes are composed of a central black hole and a surrounding accretion disk. It is indeed impossible for people to directly observe black holes with the naked eye or instruments.

Because within this range called the black hole event horizon, it is also the place where light will disappear, but at the same time due to its huge mass, it will attract countless cosmic space materials and rush towards it, becoming its "food". Generally, within the area of ​​this vortex-shaped accretion disk, it will lead to strong collision of matter, which not only produces the hottest high temperature, but also produces the most dazzling light......

Because of these astronomical phenomena, it not only makes it one of the brightest stars in the universe, but also allows astronomers to obtain a lot of data and calculate more information about it from the side. For example, the brightness of this Ton618 black hole is about the sum of all the stars in 2000 Milky Ways!

If calculated according to the area where the light disappears and is invisible, astronomers think it is a kind of planetary area. The volume of the black hole is also called the event horizon volume, if we define this as the edge of the black hole!

The volume of the Ton618 black hole will be a super disk with a diameter of about 390 billion kilometers. Even the largest star UY Scuti can only be a little brother in front of it, and its diameter is only 1/165 times its size!

The volume of the Ton618 black hole will be about 4.5 million times that of the largest star. If you want to fill this black hole with our sun, even if the volume is not compressed, you must prepare at least 200 million. If it is replaced by the earth, You have to prepare 260 trillion trillion Earths...

If you include its periphery, such as the accretion disk of this super black hole, its width can be extended to more than 1 light-year!

All of this is also limited by our human ability to observe, and the vastness of the universe may be far beyond what you and I think. But it is precisely because of these interesting and unknown existences that we are full of curiosity about the world.