Stars are gas balls, so why are they so dense

Usually when we talk about the physical state, such as the gas sphere, we refer to the surface state, and the sun says that there is still a solid state in it.

There are six states of nature, plasma, gaseous, liquid, solid, supersolid, and neutron.

Maybe there is super-solid matter in the sun.

Yes, it's hard to imagine, for example, the sun is a ball of gas, because its volume and mass are too large, the density of gas is unimaginable, in the sun, gas is 8 times denser than iron! That is, if you can take a cloud of gas from the sun, the iron will float in it!

In short, it is due to the large size and mass of stars.

Because stars are very massive, their gravitational pull is also very large, and the gas is compressed.

When the gravitational force is high, the density is naturally great.

Gas balls? This gas must be particularly dense.

The balloon can be made into different sizes, and the name of the star can be written according to the size of the star, which can be more intuitively understood.

Top 10 largest stars in the universe

1. The constellation Uy is 5 billion times larger than the Sun.

It is the second largest star rich in hydrogen, and it is 215 times more massive than the Sun.

3.NML Cygnus is a red supergiant and one of the ten largest stars in the universe, rich in oxygen, and its radius and mass have not been determined so far due to the dust and some opaque material around it. Trembling.

4.The Cygnus supergiant is located in the constellation Cygnus, which is 25 times more massive than the Sun and 300,000 times brighter than the Sun, making it one of the brightest stars known.

5.Cepheid, also known as the Pomegranate Star, is a red supergiant located in the constellation of Caspheus, known for its red color, with an equal brightness, and a luminosity of 350,000 times that of the Sun, making it one of the brightest stars known.

6.V838 Monocerotid is a red supergiant located in the constellation Monolithos, about 5-700 times the diameter of the Sun.

7. WOH G64 is a red supergiant located in the Big Magellanic Galaxy, with a diameter of about 1540 times that of the Sun and a mass of 40 times that of the Sun, and is also one of the largest known stars.

8.KW Sagittarius is a red supergiant located in the constellation Sagittarius, with a radius 1460 times that of the Sun, and one of the ten largest stars in the universe. Due to a lack of information, its distance from the Sun cannot be determined.

9.Cactus V354 is a red supergiant located in the constellation C. Cactus, with a radius of about 1520 times that of the Sun, and because it is surrounded by dust, it is generally invisible to the naked eye, in addition, it is worth mentioning that C. Cactus V354 may have a supernova in the future**.

10.Betelgeuse, also known as Orion, is a red supergiant star and one of the top ten supergiants in the universe, with a radius about 1,180 times that of the Sun, and one of the largest stars visible to the naked eye.

NASA is on an ambitious mission to study stars using balloons the size of a football field.

The spherical shape of the stars is due to the combined action of various gravitational forces, strong forces, weak forces, etc.

The basic conditions for the production of stars are hydrogen, gravity, and a long time to make stars.

Initially, a small piece of hydrogen in the nebula heats up and begins to heat up, causing other substances in the aftercloud to heat, heat, and emit light. Dust and gas begin to gather under the action of gravity, forming huge whirlpools. In the process of aggregating and compressing the volume, the temperature of the compressed gas increases according to the first law of thermodynamics due to the work done to it by the outside world.

Over hundreds of thousands of years, nebulae will increase in density and form disk-shaped vortices that are larger in diameter than the solar system. And the gas in the center, under the continuous compression of gravity, forms a sphere with ultra-high density and temperature.

The more massive a planet is, the more round it is. Conversely, if the mass is small and the gravitational pull is small, the star may not be round. In fact, in addition to the nine planets, there are many asteroids with very small masses in the solar system, and their shapes are not very regular, and some look like a large rock.

Broadly speaking, the density of stars in the main-sequence phase is not large.

But the density of stars is gradient, that is, the closer to the center, the denser it becomes; The closer you get to the outer layer, the less dense it becomes.

Take the sun, for example. The average density of the Sun is about that, slightly heavier than water (think about it, the average density of the Earth is g cm 3). But the density of the center of the Sun is as high as about 150 g cm3, while the density of the photosphere (the layer we see) is only 10 (-9) g cm3, which is more "vacuum" than the best artificial vacuum on Earth.

Stars that are less massive than the Sun also have a slightly lower average density than the Sun. Stars larger than the Sun, because gravity and radiation pressure must be balanced, have an average density slightly larger than the Sun, but not much worse than the Sun.

In the later stages of star evolution, it will expand into a red giant, and the average density will decrease greatly due to the increase in volume. The average density of a typical red giant is only about 1,100 times that of water. But there is also a density gradient.

The density of the center increases to 800 1000 g cm3, while the density of the outer gas is only tens of billions of a gram cubic centimeter. It's like a vacuum.

When the outer gas of a red giant disappears, the inner stellar nucleus is revealed, which is a white dwarf. Therefore, the density of white dwarfs is about 800 1000 g cm3, and white dwarfs also have density gradients, but the density gradient is not large.

When a massive star becomes a red giant or red supergiant, it ends its life as a supernova explosion. After a supernova explosion, the star's shell is blown apart and runs away, and the star's nucleus continues to shrink and becomes a neutron star or black hole.

Neutron stars are formed when a star explodes in a supernova, when external pressure compresses the nucleus inward, presses electrons into protons, and turns them into neutrons. The density of a neutron star is the density of the nucleus of an atom, which is about 10 14 g cm3, or 100 million tons of cubic centimeters.

Under the current laws of physics, there is no star that is heavier and denser than a neutron star

As for the density of black holes, since all the laws of physics are completely invalid in black holes, the state of existence of matter in them is not yet known, and the density of black holes is not known.

Yes, all stars are gaseous, there is no liquid, and there is no solid.

Stars are dependent on internal nuclear fusion reactions.

The resulting outward radiation pressure is stable in equilibrium with the inward gravitational force. Intense nuclear fusion reactions are taking place in the interior of the star all the time, and a large amount of energy is produced, keeping the interior of the star at a temperature of at least 12 million degrees, even on the surface of the star, the temperature is not lower than 2,000 degrees. At such high temperatures, it is also impossible for any substance to remain in a solid and liquid state, and can only exist in a gaseous state.

At the same time, even the gaseous state is not a stable atomic state. The high temperature detachs the outer electrons of the atom from the nucleus.

Becoming free electrons and positively charged ions, this state is called the plasma state.

So, stars are made up of plasma gases.

Sometimes, stars are also referred to figuratively as "giant balls of hot gas".

No. Because the definition of a star is to have a fusion reaction, the celestial body that will shine and heat can be called a star, whether it is a main-sequence star or a red giant, an orange giant, a blue giant, or a neutron star after the death of a star, a white dwarf, an orange dwarf, a magnetar, a pulsar, a black hole, etc., are all luminous and heated, if a star is not glowing, its interior will collapse and explode due to the loss of energy support, so it is impossible for a star that does not emit light to exist.

Jupiter, if the mass and pressure temperature are high enough to produce a fusion reaction, will also change from a planet to a star.

That's right, all stars are gaseous planets.

The high temperature of the star makes it impossible for any matter to remain liquid or solid, only gaseous. That's why some people say: "Hengyou buried stars are huge hot gas balloons".

However, matter in stars does not exist in the form of atoms or molecules. At temperatures of thousands to tens of thousands of degrees on the surface of a star and tens of millions to hundreds of millions of degrees inside, all matter cannot form molecules (i.e., cannot form stable chemical bonds, even atomic nuclei.

Some of the electrons on the outside will run away. Therefore, in the constant noise permeable star, it is a gas composed of ions with different degrees of ionization and an equal amount of free electrons. It's called the plasma state. Gas.

Stars belong to the plasma state.

When a star reaches old age after passing through its youth, it first becomes a red giant, then a white dwarf, and finally a neutron star. So, broadly speaking, these are stars. Since the universe as we know it is only the tip of the iceberg, so there is no one maximum density, and most of the planets in the same period have similar densities, only the average density of stars in different periods is described here.

In the case of the sun, for example, its density is now 》3, and in another 45 billion years, its density will be as high as 》4

g cm>3, and then a billion.

The mass of a star is the physical quantity of a star and is the determinant of star structure and evolution. Using the orbital motion of binary stars is the most fundamental and reliable way to determine the mass of a star. Generally, the mass of a star is in the mass of a sun.

Most stars are in the mass of the Sun, and most of the large stars in the spiral arms of the Milky Way are mostly 6 to 60 times the mass. If a star is as massive as it is, it is very unstable and difficult to exist. If the mass of a star is too small, its core temperature and pressure are not enough to produce energy for a long-lasting and efficient nuclear reaction, that is, it cannot become a celestial body with stellar properties.

One of the most massive stars known is HD93250, which has a mass of about 120 times the mass of the Sun. The mass of the host star and companion star of HR2422 is about 59 times that of the Sun, the mass of the host star of the Horn Defence double star is about 10 times that of the Sun, the mass of the two stars in the five cars and two binary stars is the sum of the mass of the Sun, and the mass of the main star of Sirius is twice that of the Sun. The least massive star is VV in the constellation Cetus, which is a pair of binary stars, the larger one has a mass of 8 of the mass of the Sun and the smaller one has only 4 of the mass of the Sun, and this small one has lost its qualification as a star.

75 white dwarfs have a mass twice the mass of the Sun, and many red dwarfs have less than half the mass of the Sun or even less than 1 10 of the Sun. It can be seen that in the stellar world, the mass of the Sun is also in the middle of the world. Of course, there are still not many stars whose mass has been accurately measured, and there is still a lot of research to be done.

The average density is obtained by dividing the volume by mass. The difference in diameter between stars is more than 100 million times, while the difference in mass between stars is only a few thousand times. It follows that the difference in stellar mass is much smaller than the difference in volume.

It's not hard to imagine how striking the difference in density between stars is. The density of the earth is times that of water, and the average density of the sun is only twice that of water. The density of stars in the main sequence earlier than the Sun is less than 1, and the density of dwarf stars later than the Sun is greater than 1.

As giant red supergiants in the stellar world, their volume is millions or hundreds of millions of times larger than the sun, but their mass is only dozens of times larger than that of the sun, and their average density is only one million, tens of millions, or even billionths of water, and their thinner degree can be imagined. For example, the average density of the red supergiant of the Cepheid VV is almost the same as the vacuum in a laboratory. In the stellar world, neutron stars and white dwarfs are surprisingly dense, with a density of 101 kilograms, 3,1 cubic centimeter, and the weight of such material is tens of tons, and they are surprisingly small in size, but their mass is comparable to that of the sun.

Neutron stars have densities of 10117 1018 kilograms3, which is a super-dense state that cannot be achieved in the laboratory.