Why is the universe vacuum? Is the universe vacuum?

This is the problem of gravitation, there is a gravitational attraction between any two objects, and the reason why there is an atmosphere around the earth (the difference between vacuum and non-vacuum is whether there are gas molecules in a particular space) is because of the attraction of the earth to the atmosphere (the greater the mass of the object, the greater the gravitational pull). The mass of the Sun is greater, so it can attract the 9 planets around him, and the mass of the Earth is smaller, so it can attract the Moon around him. And stars (such as:

The distance between the sun) is large, and as the distance between the objects increases, the gravitational force between the two objects decreases. Where there is no stellar attraction, there is a vacuum. The universe contains many stars, and there are no gas molecules outside the star's ability to attract, which is a vacuum.

The second meaning of the universe is matter, so it is not vacuum.

We can't get a vacuum, and what Einstein said is that light will slow down after being blocked by **, so light will not be blocked by matter in a vacuum, so the speed of light in a vacuum is the fastest speed of light, which has theoretical reference significance.

Light is confirmed to be an energetic particle, and photons are one of the elementary particles, so light can propagate in a vacuum, and photons exhibit wave properties in the process of propagation, which is the wave-particle duality of light.

The spacecraft is lifted off by the thrust of the launch vehicle from the ground to the orbit stage; The spacecraft operates in orbit by inertia; The orbit change of the spacecraft is achieved by starting the orbit change rocket on the spacecraft.

The principle of operation of rockets, whether in the atmosphere or in a vacuum, works according to the "principle of conservation of momentum", that is: mass velocity (of the rear jet) = mass (forward) velocity of the (spacecraft).

Not an absolute vacuum, just an approximate vacuum. Space cannot transmit sound.

In the vast space of the universe, in addition to various stars, there is a lot of matter, and what we call space is not an absolute vacuum. Scientists have observed the presence of gas, dust, and clouds between the stars, collectively known as interstellar matter.

The total mass of interstellar matter accounts for about 10 of the total mass of the Milky Way, which is not small in terms of numbers. However, due to the vastness of the Milky Way, the density of interstellar matter is particularly small, averaging 10-12 grams cm3, which is equivalent to 1 hydrogen atom per cubic centimeter. This density is a high vacuum that is far from being reached in laboratories on Earth, with the highest vacuum currently being 10-12 mm of mercury, equivalent to 10,000 particles per cubic centimeter.

The temperature of interstellar matter varies greatly, with low temperatures of only a few degrees and bases close to absolute zero; The high ones can reach tens of millions of degrees.

Interstellar matter is unevenly distributed within the Milky Way. The density of interstellar matter varies greatly between regions, from interstellar gas and dust to interstellar clouds when they aggregate into a density of more than 10 103 particles per cubic centimeter, and intercloud densities as low as particles per cubic centimeter. Interstellar matter is concentrated in the galactic spiral arms.

Interstellar gases include gaseous atoms, molecules, ions, electrons, etc., and the elemental abundance of interstellar gases is similar to that of the universe, with hydrogen being the most, helium being the second, and other elements being very low. This is related to the origin and evolution of the elements, and also indicates the unity of matter in the universe.

Interstellar dust is solid particles 10-5 10-6 cm in diameter, dispersed in interstellar gas. The total mass of interstellar dust accounts for about 10 of the total mass of interstellar matter. Interstellar dust may be composed of ice-like substances such as water, ammonia, and methane, minerals such as silica, magnesium silicate, and ferric oxide, as well as graphite grains.

Interstellar dust scatters starlight and weakens it, a phenomenon called interstellar extinction. Interstellar dust has a great influence on the formation of interstellar molecules, on the one hand, it prevents the ultraviolet radiation of starlight from dissociating interstellar molecules, and on the other hand, it acts as a catalyst to accelerate the formation of interstellar molecules.

Interstellar matter can be searched for by measurements of the electromagnetic spectrum. Interstellar ions were first discovered in 1904, the presence of interstellar dust was confirmed by the observation of distant stars turning red in 1930, and the presence of 105 107 high-temperature gases was confirmed in 1977.

According to modern theories of stellar evolution, interstellar matter aggregates into early stars, which in turn send matter into interstellar space through explosions, ejections, and loss.

It's not that there's nothing in a vacuum, it's just that the density of matter is very low, like one atom per cubic kilometer. The distribution of matter in the universe is not uniform, and in some places there are dense areas called nebulae. Of course, it's not that dense.

cubic kilometers. That's how the atom goes. The universe is cold, and hydrogen, helium, and all of these substances are solid, unless they are massive.

Well, now how it came to be. In a nebula, two atoms that are close to each other are pulled together by gravity. Gravitational force The gravitational force of these four forces is comparatively smaller, but it is produced under relatively low conditions:

As long as there is mass, there will be gravity.

<> at first, this power will slowly pull them closer, but over time, they will eventually come together. After they are combined, they will continue to approach the direction of motion of the atoms - they are all the gravitational direction around the atoms, so the specific flying is uncertain, but it doesn't matter, they will eventually coalesce into small groups, and in the process of rubbing back and forth or losing electrons, some of them will be electronic, and then there is an electrostatic force, which is a force that is much stronger than the gravity force, and the conditions for generating the electrostatic force are more harsh and require an electric charge.

But because he's bigger, he's accelerating the integration of these smaller groups. At this point, you can imagine that when the boiling water vapor condenses into small water droplets on the pot, these droplets gather on a large scale (on a light-year scale), but because even in nebulae, the distribution of matter is not uniform, slowly in the rich material region can form a larger material region than elsewhere, and this region continues to attract external matter. You can think of it like a bathtub that empties the water, where all the surrounding material sinks into the hole in the middle.

Because it is large enough, the gravitational pull is strong enough to break the strong interaction force, forcing the two hydrogen nuclei together to form a helium nucleus. It releases a lot of energy, and that's when the star glows. It is not in vain to run out of energy, he will push the hydrogen out, the outside is equivalent to a large **, but the gravity is too strong for them to operate, and the repulsion of **, and the gravitational pull of gravity will eventually reach equilibrium, and the star will become a constant, but at this time, if there is material in the nebula that continues to suck in the star, the star will have a large ** in the celestial body that is not broken, just like if you put a light bulb in the drainage hole of a bathtub, the matter will sink into the bright hole.

A vacuum in the true sense of the word refers to a space where there are no particles of energy and momentum that do not exist. Savor this sentence carefully, and you will immediately realize that there can be absolutely no "vacuum in the true sense of the word". Because particles with energy and momentum include not only the atoms and molecules that make up common matter, but also photons and even neutrinos, in short, nothing in a vacuum.

It's okay to say without photons, but without neutrinos, it's almost impossible.

The universe is often filled with vitality, air currents, and life astral air currents, forming a cosmic magnetic field, so it is never a vacuum.

It is because the universe is made up of tiny particles, and if these particles do not exist, then the universe will have no vacuum. is a medium.

Low, medium, or high vacuums can all be achieved by pumping, but a vacuum in the true sense of the word refers to a space where there are no particles of energy and momentum, but this is absolutely impossible.

The cosmic region barely measures any pressure, it is infinitely close to a vacuum, but it is not a vacuum in the true sense of the word.

In contrast to the Earth's environment, the universe is a vacuum.

After leaving the earth's atmosphere and entering the universe, there is no air, no atmospheric pressure, no sound, closed operation and heat transfer, which is a vacuum environment.

But in fact, the universe is not blind, it is a complete vacuum. Even in the space between galaxies and galaxies, there are 2 5 atoms or molecules of matter per cubic centimeter, so it cannot be said that there is nothing at all. In the space of the solar system beyond the Earth, the number of atoms (molecules) can reach dozens, and although it is more "vacuum" than the best vacuum that can be artificially created on Earth, matter still exists.

Even in a small area of the universe, if all the substances, atoms and molecules in it are removed, according to the theory of the quantum universe, there is also a vacuum zero point energy in it, and it is not nothing.

It can be approximated that the universe is vacuum.

From a mechanical point of view, as long as the pressure is less than one standard atmosphere, it is a vacuum. By this definition, the universe must be vacuum.

Moreover, the vacuum of the universe is quite high, and the best instruments on earth cannot reach the vacuum level of the universe.

Most of all the atoms in the universe are vacuums, but vacuums are not really empty. According to the theory of quantum physics, vacuum fluctuations persist after the complete disappearance of light and radio waves in a vacuum. In fact, those vacuum fluctuations are essential to our existence.

Although light is an electromagnetic wave, unlike mechanical waves, it has wave-particle duality, and photons are a kind of particle. Space is not a vacuum, but it is generally considered a vacuum;

Thank you for asking a question [heart].

What is the singularity.

Answering a singularity is usually a point that is called undefined when it is a mathematical object, or when it is so unordered in special circumstances that it appears in a set of exceptions. Such as derivatives. The singularity is a mathematical concept that begins in calculus to refer to the point at which the condition of breaking the continuity of a function.

In physics, it refers to the point at which the curvature of space-time becomes infinity in space-time.

No, there are places where an atmosphere will form, and there will be air, and there will be many places in the universe, but we haven't explored it, so we can't be sure.

Not necessarily. This is because there are many unsolved mysteries in the universe, and there are many undetected places, so it is not certain whether they are all in a vacuum.

The whole universe should be in a vacuum, because we don't know much about the universe yet, so the universe should be in a vacuum now.