In order for the fire to burn for a long time, firewood must be constantly thrown into it. We all know about it. But the question is, why doesn't the sun go out? Why does the sun burn for many billions of years and still shine brightly and heat hot? What kind of fuel does not allow the sun to go out? And why is the sun always so hot? How many whys are asked by our little "whys". Well, let's try to answer their questions.
Once, a long time ago, scientists thought that coal was burning, but after calculating how many years this fuel could last for the sun, they were surprised that all the coal should have burned out long ago and then go out.
Time passed, and the sun did not even think to go out and seemed to laugh at the scientists: “Aha! Can't guess my main secret! You don't need to know my deepest secrets, it's enough that I keep you warm." "What do you mean why?" - the scientists were even more surprised, “if you solve your secret, then on our earth you can create many small artificial suns! After all, your solar energy is very cheap compared to other types of energy.
For example, people have to mine coal from under the earth and load it onto huge railway platforms. Drive this unthinkable amount of coal to power plants so that they generate electricity. And then, the resources of the planet are not endless, every year, coal and gas on earth is becoming less and less. Their reserves are disappearing faster and faster because humanity needs more and more energy. And your solar energy reserves are endless. And to get solar energy, you do not need to dig deep wells for oil or build underground mines for coal. That's why we need to know what kind of magic firewood you, the sun, are burning on.
Indeed, if such "firewood" were found, then all the technology of the earth would begin to work, only on the energy of the sun. This energy would warm and illuminate our homes, would become an indispensable assistant in growing vegetables and fruits.
But still, our scientists managed to solve the riddle. They have learned to transform matter, I transform it into each other. For example, hydrogen gas, scientists turn helium into gas. Or helium is converted into solid carbon. And if you need to turn solid carbon into magnesium metal, they do that too. They can turn magnesium into silicon, and silicon itself into ordinary silicon, from which quite a lot of necessary things can be made.
Scientists, despite the difficulties, have achieved very good results and found that when one substance is converted into another, very a large number of! Scientists call this a reaction. And this is a huge breakthrough in terrestrial science. Imagine that instead of huge mountains of coal, a small pea - a substance - will be loaded onto the ship. When this pea-substance is transformed into another substance, it will release so much energy that it will be enough for a very long voyage.
But, unfortunately, so far all this is in theory, because in order for such transformations to become a reality, such special conditions are necessary, it is still impossible to create. But scientists are sure to come up with something. And they will create the same conditions as in the sun, in some small container. After all, similar reactions constantly occur in the sun: hydrogen is converted into helium, and helium is converted into carbon, ... therefore, the sun does not cool down for a very long time and is unlikely to cool down in the near future. He is destined to burn for many billions of years!
I think it's no secret to anyone that our sun and the stars that we see at night in the sky are the same. That's just the "night" stars are farther away from us than the sun.
Stars- These are huge spherical accumulations of hot gas. As a rule, stars consist of more than 99% from gas, the remaining fractions of a percent account for a huge number of elements (for example, there are about 60 of them in our sun). The temperature of the surfaces of various types of stars ranges from 2,000 to 60,000 degrees Celsius.
What makes stars emit light? Ancient thinkers thought that the surface of the sun was constantly on fire, and therefore radiated light and heat. However, it is not. First, the reason for the emission of heat and light is much deeper than the surface of the star, namely in core. And secondly, the processes occurring in the depths of stars are not at all like combustion.
The process that takes place in the interior of stars is called. In a nutshell, thermonuclear fusion is the process of converting matter into energy, and an incredible amount of energy is released from a minimal amount of matter.
From a scientific point of view, this is a reaction in which lighter atomic nuclei - usually isotopes of hydrogen(deuterium and tritium) merge into heavier nuclei - helium. For this reaction to occur, an incredibly high temperature is required - several million degrees.
This reaction takes place in our sun: at a core temperature of 12,000,000 degrees, 4 hydrogen atoms merge into 1 helium nucleus and an unimaginable amount of energy is released: heat, light and electromagnetism.
How could you guess the sun forever, it will "burn itself" over time. Scientists believe that there is still enough matter in it for about 4-6 billion years, i.e. somewhere as long as it has already existed.
It's hard to believe, but those stars that shine at night from the sky, and the Sun that illuminates us during the day, are one and the same. Why does the Sun shine during the day and not at night like "normal" stars? Let's dive into the science.
Details about the sun
The sun is the star closest to our planet. The Sun is the center of our planetary system, which got its name from the name of the star - Solar.
The distance from the Earth to the Sun is approximately 150,000,000 kilometers. The mass of a star named the Sun is 330,000 times greater than the mass of our planet. At the same time, the Sun is not a solid body, like the Earth, but is a spherical accumulation of hot gases.
If someone does not believe in the gaseous nature of the Sun, then just imagine: the temperature on its surface is approximately 6000 degrees Celsius. The core (central part) of the Sun is heated to millions of temperatures. No material, alloy or element currently known to science will be able to maintain a solid state at such temperatures.
Why the sun shines: a scientific explanation
It used to be believed that the Sun shines due to the burning of the elements that make up its composition. But according to rough estimates, even rough ones, it cannot “burn out” for billions of years, the Sun should have gone out a long time ago, having lost mass, thereby breaking the gravitational balance in the system of planets and letting them float freely across the expanses of the Galaxy. But this does not happen, the Sun has been shining for billions of years and does not think to dry up. What makes the sun shine?
Scientists have found and proved that the glow of the Sun is the result of the release of colossal amounts of energy obtained as a result of thermonuclear processes occurring in it.
Thermonuclear processes are remarkable in that when matter is consumed, millions of times more energy is released than during combustion. Yes, that's why thermonuclear energy is the future, its minus is the complexity of starting the reaction. To start a thermonuclear reaction requires a huge amount of energy and complex types of consumables, such as synthetic uranium or plutonium.
Why does the sun shine during the day and not at night
Everything is simple here. The very phenomenon of night is the turn of a part of the planet with its "back" to the Sun. And since the planet rotates uniformly around its axis, and the revolution takes about 24 hours, it is easy to calculate the time allotted for the night - 12 hours. So it turns out that half of the Earth is turned towards the Sun for 12 hours and it illuminates it, and in the remaining 12 hours it is on the other side of the globe, not illuminated by the Sun. It turns out that when the Sun shines, we have day, and when the Sun does not illuminate our part of the Earth, we have night. Phenomena such as morning and evening are side effects caused by the ambiguous nature of light and the concomitant effect of diffraction.
So, knowing now why the Sun shines, you should also find out how much he has left to please us. This is about 5 billion years, after losing about a percent of its mass, the Sun will lose stability and go out.
Stars radiate huge amounts of heat and light for many billions of years, which requires a huge amount of fuel consumption. Until the twentieth century, no one could imagine what kind of fuel it was. The biggest problem in physics was the big question - where do stars get their energy from? All we could do was look up into the sky and realize that there was a huge “hole” in our knowledge. To understand the secret of the stars, a new engine of discovery was needed.
Helium was needed to unlock the secret. Albert Einstein's theory proved that stars can get energy from within atoms. The secret of the stars is Einstein's equation, which is the formula E \u003d ms 2. In a sense, the number of atoms that make up our body is concentrated energy, compressed energy, energy compressed into atoms (particles of cosmic dust) that make up our universe. Einstein proved that this energy could be released by colliding two atoms. This process is called thermonuclear fusion, it is this force that feeds the stars.
Imagine, but the physical properties of a small, subatomic particle determine the structure of stars. Thanks to Einstein's theory, we have learned how to release this energy inside the atom. Now scientists are trying to simulate the source of stellar energy in order to gain power over the power of fusion in the laboratory.
Inside the walls of the laboratory, near Oxford in England, is the machine that Andrew Kirk and his team are turning into a "star" laboratory. This installation is called Tokamak. It's basically a big magnetic bottle that holds a very hot plasma that can simulate conditions like the inside of a star.
Inside the Tokamak, hydrogen atoms oppose each other. To push the atoms against each other, the tokamak heats them up to 166 million degrees, at which temperature the atoms move so fast that they cannot avoid colliding with each other. Heating is a movement, the movement of heated particles is enough to overcome the repulsive force. Traveling at thousands of kilometers per second, these hydrogen atoms crash into each other and combine to form a new chemical element, helium, and a small amount of pure energy.
Hydrogen weighs a little more than helium, in the process of combustion the mass is lost, the lost mass is converted into energy. A tokamak can support the fusion of a fraction of a second, but in the interior of a star, the fusion of nuclei does not stop for billions of years, the reason is simple - the size of the star.
A star lives by gravity. That's why the stars are big, huge. To compress a star, you need a huge force of attraction in order to release an incredible amount of energy, enough for thermonuclear fusion. This is the secret of the stars, this is why they shine.
Synthesis in the core of the sun's star generates every second the power that would be enough for a billion nuclear bombs. A star is a giant hydrogen bomb. Why doesn't it just shatter into pieces then? The fact is that gravity compresses the outer layers of the star. Gravity and synthesis are waging a grand war, the attraction of which wants to crush the star and the fusion energy that wants to blow the star apart from the inside, this conflict and this balance create a star.
This is a struggle for power that continues throughout the life of a star. It is these fights on the stars that create the light and each ray of the stellar journey makes an incredible journey, the light travels 1080 million kilometers per hour. In one second, a beam of light can circle the earth seven times, nothing in the universe moves so fast.
Since most stars are very far away, light travels hundreds, thousands, millions and even billions of years to reach us. When the Hubble orbiting space station peers into the far corners of our universe, it sees light that has traveled for billions of years. The light of the Etequilia star that we see today set off on its journey - 8,000 years ago, the light of Betelgeuse has been on its way since Columbus discovered America - 500 years ago. Even the light of the Sun flies to us for as long as 8 minutes.
When the sun synthesizes helium from hydrogen, a particle of light, a photon, is produced. This beam of light has a long and difficult journey to the surface of the Sun. The whole star prevents it, when a photon appears it crashes into another atom, another proton, another neutron, it doesn't matter, it is absorbed, then reflected in a different direction and moving so chaotically inside the Sun, it has to break out.
The photon will have to rush wildly, crash into the atoms of the gas billions of times and desperately rush out. It's funny, in order to get out of the core of the Sun, it takes a photon thousands of years and only 8 minutes to fly from the surface of the Sun to the Earth. Photons are sources of heat and light, thanks to which diverse and amazing life is supported on our planet Earth!
A growing man is interested in literally everything. He asks questions about everything he sees. Why does the sun shine during the day and the stars at night? And so on and so forth. Answering seemingly simple questions is not always easy. Because sometimes some special knowledge is not enough. And how to explain the complex in a simple way? Not everyone can do this.
What is a star?
Without this concept, it is impossible to clearly explain why the sun shines during the day, and the stars at night. Often, the stars appear to babies as small dots in the sky, which they compare to small light bulbs or flashlights. If we draw an analogy, then they can be compared with huge searchlights. Because the stars are unimaginably huge, incredibly hot and located at such a distance from us that they seem like crumbs.
What is the sun?
First you need to say that the Sun is a name, like a name. And this name is the closest star to our planet. But why isn't she a dot? And because of what the sun shines during the day, and the stars at night, if they are the same?
The sun does not appear to be a dot because it is much closer than the others. Although it is also far from it. If you measure the distance in kilometers, then the number will be equal to 150 million. A car will cover such a distance in 200 years if it moves without stopping at a constant speed equal to 80 km/h. Because of the incredibly large distance, the sun seems small, although it is such that it could easily contain a million planets like Earth.
By the way, the sun is far from the largest and not very bright star in our sky. It is simply located in one place with our planet, and the rest are scattered far in space.
Why is the sun visible during the day?
First you need to remember: when does the day begin? The answer is simple: when the sun begins to shine from behind the horizon. Without his light, this is impossible. Therefore, answering the question of why the sun shines during the day, we can say that the day itself will not come if the sun does not rise. After all, as soon as it goes beyond the horizon, evening comes, and then night. By the way, it is worth mentioning that it is not the star that moves, but the planet. And the change of day to night occurs due to the fact that the planet Earth rotates around its fixed axis without stopping.
Why, then, are the stars not visible during the day, if, like the sun, they always shine? This is due to the fact that our planet has an atmosphere. They scatter in the air and overshadow the faint glow of the stars. After its setting, the scattering stops, and nothing blocks their dim light.
Why the moon?
So, the sun shines during the day, and the stars at night. The reasons for this are in the air layer surrounding the earth. But why is the moon sometimes visible, sometimes not? And when it is, it can take on different forms - from a thin crescent to a bright circle. What does it depend on?
It turns out that the moon itself does not glow. It works like a mirror that reflects the sun's rays to the ground. And observers can see only that part of the satellite that is illuminated. If we consider the whole cycle, then it begins with a very thin month, which resembles an inverted letter "C" or an arc from the letter "P". Within a week, it grows and becomes like a half circle. For the next week, it continues to increase and every day it approaches a full circle more and more. The next two weeks, the drawing decreases. And at the end of the month, the moon completely disappears from the night sky. More precisely, it is simply not visible, because only that part of it that turned away from the Earth is illuminated.
What do people see in space?
Astronauts in orbit are not interested in the question of why the sun shines during the day and the stars at night. And this is due to the fact that both are visible there at the same time. This fact is explained by the absence of air, which prevents the light from the stars from passing through the scattered rays of the sun. You can call them lucky, because they can immediately see the nearest star, and those that are far away.
By the way, night lights differ in color. And it is clearly visible even from the Earth. The main thing is to look closely. The hottest of them shine white and blue. Those stars that are colder than the previous ones are yellow. Our sun is one of them. And the coldest emit red light.
Continuation of the conversation about the stars
If the question of why the sun shines during the day and the stars at night arises in older children, then you can continue the conversation by remembering the constellations. They combine groups of stars that are in one place on the celestial sphere. That is, they seem to us located nearby. In fact, there can be a huge distance between them. If we could fly far from the solar system, we would not recognize the starry sky. Because the outlines of the constellations would change a lot.
In these groups of stars, the outlines of human figures, objects and animals were seen. In this regard, various names have appeared. Ursa Major and Minor, Orion, Cygnus, Southern Cross and many others. Today there are 88 constellations. Many of them are associated with myths and legends.
Because of the constellation, they change their position in the sky. And some are generally visible only in a certain season. There are constellations that cannot be seen in the Northern or Southern Hemisphere.
Over time, the constellations lost minor stars, and it became difficult to guess from their pattern how the name arose. The most famous constellation in the Northern Hemisphere - Ursa Major - has now turned into a "bucket". And modern children are tormented by the question: “Where is the bear here?”
