Why is the cosmic space through which the sunlight passes dark and cold?

Because space is huge and empty, there is nothing that can reflect the sun's rays, and there is nothing in the universe that can absorb the heat contained in the sun's rays, so space is cold and dark.

The transmission of light does not require a medium, so it is possible to see light in space, but the temperature is not good. It must be transmitted via **. There are about three modes of heat transfer, namely heat conduction, heat radiation, and heat convection.

The number of molecules in the space atmosphere is very small. There are only a few molecules in a cubic meter of space. The method of heat transfer is heat dissipation.

With so few molecules and extremely slow heat transfer, it is understandable that the universe is very cold.

Because the universe is vacuum, there is no matter to reflect light and store heat, so the space through which sunlight passes is dark and cold.

Because the light itself is invisible, when we say that we see the light, we actually see what the light illuminates. It can be said that there is nothing in space, and there is no light in things, so space is dark and ice. This also shows that light itself is cold!

In space, darkness and light coexist. Space is boundless, or the margins are so large that the stars in the universe do not emit enough light to illuminate the entire universe. <>

A star is one of many galaxies in the universe, and when all the stars in the universe are burned out, the universe no longer emits light and eventually becomes a black dwarf, and the sun is no exception.

The celestial planet looks like it is infinitely immortal, in fact, the celestial planet is the same as people, and in the end it cannot escape the fate of birth, old age, sickness and death, the sun is carrying out nuclear fusion reactions all the time, the so-called nuclear fusion reaction is to combine two lighter atomic nuclei in order to form a relatively heavy nucleus, in this stage of change, two nuclei will form a part of the mass in the form of energy in the process of forming a nucleus. In the universe, all stars are undergoing this reaction process from beginning to end. <

The hydrogen bomb was completed almost instantly, in stark contrast, the nuclear fusion reaction in the interior of the sun takes a very long time, the nuclear fusion reaction in the interior of the sun has been carried out for 4.6 billion years so far, the sun at this stage is in middle age, and in the future it will continue to carry out nuclear fusion steadily, up to 6 billion years, will gradually enter the stage of old age, which is really unimaginable. The reason why the sun burns for so long is because there are so many raw materials; Moreover, the nuclear fusion reaction area is small; At the same time, under the combined action of the sun's gravity and magnetic field, the energy inside the sun is released outward in a relatively stable way. No matter how massive the sun is in mass and volume, it will eventually burn out, and what will become of the sun one day in the future?

According to some scientific research, we can only think of the "tragic" end of the sun, the sun will gradually develop from the current prime of life to the red giant stage, after which the white dwarf will be formed due to the exploration point, and finally the black dwarf made of the C element, which is the final end of stars like the sun, and at that time, the universe will be completely dark.

The universe is empty and cold, why hasn't the sun been extinguished yet? That's because of the relationship between temperature and nuclear fusion, let's talk about it concisely with you!

The cosmic space is indeed very empty and cold, the temperature of the cosmic space far away from the stars is close to absolute zero, and the cosmic background radiation we usually talk about is actually the temperature of the cosmic space, which is usually minus 270 degrees Celsius. Only in the vicinity of the star, under the thermal radiation of the star, will the temperature be higher.

So, as mentioned in the question, why is the sun's heat still flowing in such a cold environment? This is going to talk about the ** of solar heat.

The sun belongs to the stars, and the stars are all luminous, so where does the heat of the stars come from?

In fact, it is very simple, the ** of heat is caused by the gravitational pull of the star itself.

When the mass of the celestial body reaches a certain critical point, it is currently calculated that this critical point is about a multiple of the mass of the Sun, that is, about 1 10 solar masses. When the celestial body reaches this mass, the pressure in its core region will reach a very large level, and the pressure will cause the temperature to rise, and the core temperature can reach 10 million degrees, and after reaching this temperature, the hydrogen element in the core will react.

This reaction is known as nuclear fusion, which is commonly referred to as the fusion of hydrogen into helium。In the process of fusion, a portion of the mass will be converted into energy, which will be transferred to the outside world in the form of light, rays and heat. That's where we see stars glowing.

Like the sun, every second, about 600 million tons of hydrogen will undergo fusion reactions in the core area, and 4 million tons of hydrogen will be converted into energy to provide the sun with continuous light and heat.

In fact, the sun's energy will always be emitted into the cold cosmic space, but it will not be extinguished by constantly generating new energy inside it。If no new energy is generated, then the sun would have been extinguished long ago.

The life span of the sun is very long, and it has not yet entered the old age, so the sun will not go out, and the sun is still young and strong.

Because the sun heats itself, and the sun is a hot sphere, the sun can never be extinguished.

The mass of the sun accounts for more than 99% of the mass of the entire solar system, and its interior is filled with large amounts of hydrogen and helium, which can sustain billions of years of combustion without depletion.

Because the sun is so large, it doesn't go out so easily.

Because space is so big, even if the light can illuminate some places, there are still places in space where the sun can't shine.

Because the sun is too small to light up space when compared to space.

Because the universe is too big, there is no way to light it up, the universe is very dark inside, and the universe is very dangerous.

The sky is too big and the sun is too far away from the earth, and this is the case, and it is impossible to illuminate it completely.

Every morning, we start our day with the sun shining on us. The importance of the sun to humanity is self-evident. It provides us with light and heat so that humanity can survive in this vast universe.

From the perspective of the whole universe, the earth is lonely, and the human beings on the earth are also lonely. Humanity has yet to find any other planet with signs of life. Therefore, from the perspective of the universe, the existence of human beings may be just a coincidence, which also makes human beings seem particularly small and lonely.

Now, while we humans are already exploring the universe to the best of our ability, hoping to find human companions, with little effect.

In addition to the fact that human beings are too weak, there is also the reason why the universe is too big. If you look at it from a large enough perspective, the Earth is actually suspended in a "void". Around the earth, there is only one moon that will never leave the moon.

From this point of view, the earth is not so lonely. At least until the universe is accompanied by the moon. But according to the feelings of people who have been to the moon, the surface of the moon is very cold.

There really is some meaning of Guanghan Palace. Moreover, this partner of the earth, and know that the orange did not bring companionship to mankind. There is also no life on the moon.

At least in the current solar system, no human beings have detected the existence of life. Therefore, human beings have no "neighbors" in the solar system. Not only that, but on other planets, it often feels cold.

Not only is it cold, but it also feels hot and cold, as if living in ice and fire. It seems that only the earth is warm and gentle. Why is that?

First of all, all the planets in the solar system are centered around the sun, and the sun provides light and heat to all the planets. It's just that some are too close to the sun and too hot, and too far from the sun and too cold. This is mainly because of the difference caused by the distance between the planet and the sun.

The Earth's location from the Sun is particularly suitable, neither cold nor hot, and it is precisely at this temperature that life on Earth is born. But other planets are also exposed to the sun, so why do some planets only feel light but not heat? This is mainly caused by the atmosphere that the Earth possesses.

This layer of the atmosphere is able to retain the warmth from the sun. Other planets, because they don't have this atmosphere, can't retain the sun's heat, but instead return the sun's heat to the universe. So, it's always cold in space.

And most of the universe is "void". Such a universe cannot receive the heat of the sun, and it will not be able to retain the sun's light.

The existence of human beings in the universe is indeed rare. After all, until now, humans have not discovered the existence of other life. On the contrary, in the exploration of the universe, I feel more and more small and doubt the meaning of existence.

Everything in the universe is basically measured in light years and billions. The existence of human beings in the universe is too short, so short that we can make a one-minute animation of the universe from its birth to the present, and we may not find the point where human beings exist. However, we still have the planet to rely on.

It will also be the eternal home of mankind.