If starsA- This hot clot of gas, inside which there's always something like an explosion going on with the release of energy and matter, then why is there starlight from the planet flickers? It turns out that it's all about Earth's atmosphere. Permanently appear in the air air currents, as well as the atmosphere of the planet heterogeneous, due to which the incident rays are distorted- they reach the Earth's atmosphere straight forward, and entering it refracted, turning into some kind of zigzag or wave with smooth bends. We look at the sky from one point (more precisely, the point is our eye), which picks up this signal that is either “lost” or reappearing. It's easy to lose count! It is noteworthy that scientists have discovered how many stars can you see in the night sky- near 6000 shining points, 3000 from one hemisphere and the same number from the other. It's just a pity that people don't often raise their heads to see the whole galaxy of bright celestial bodies, and exhaust fumes and city smog completely fill the access of curious people to the night sky. One day, the shutdown of some factories in one of the states led to the fact that a filled black painting with stars. People, having not seen such a sight before, began to call the emergency services in panic, claiming that they saw a UFO in the sky. Some seriously thought that an alien invasion had begun.
Living flame
Stars are not just a generator of gas and energy, they are similar to alive body. In astronomy there is such a thing as stellar evolution. Stars born from gas and dust clumps, develop and grow. After serving its life cycle, the star begins to run out of elements. First running out of hydrogen, the consequence of which is enhanced synthesis of carbon and helium- star increases at the rate of. Then she begins to actively lose gas, dispersing it throughout space, also continuing to grow. At the end of its development, a star can turn into:
Light from the past
Stream of light, or photons(particles of light) has enormous speed - about 300 thousand kilometers per second. This speed cannot be perceived with the naked eye: on Earth, the propagation of light occurs quickly due to the fact that the usual distance that we observe is slightly for such speed. But on the scale of space, everything happens differently - It takes light 8 minutes to travel the distance from the Sun to the Earth. That is, we observe light that appeared a few minutes ago; and if the Sun goes out instantly (don’t be afraid, this cannot happen), then we will understand this only after 8 minutes, until the remnants of sunlight reach us. Other stars visible to us are located much further than the sun, and the light flux from them reached us millions of years. We see the light from distant past. Maybe these stars have long moved to a new stage of development, maybe they merged with others. To bring the future at least a little closer, there are powerful telescopes. With their help it is possible to overcome huge distance and reduce time the arrival of light - to see the past, but not as distant as we see with the naked eye. This fact prompted scientists to thought experiments:
Stars- these are ours guides to the past. They reveal to us the mysteries of antiquity, tell us the eternal legends of dark and cold space. Star Light- a path that can take a person from Earth to distant planets, galaxies, to the very edge Universe. Humanity still has a lot to learn about these shining celestial bodies, and who knows, maybe we will find discovery of a new stellar secret.
Which we see as a small luminous point in the night sky. In fact, all stars are huge balls consisting of hot gases. They contain ninety percent hydrogen, a little less than ten percent helium, and the rest - various impurities. At the center of the ball the temperature is approximately six million degrees. This value corresponds to the limit that allows the free flow of hydrogen into helium during this chemical process. As a result, a huge amount is released which is transmitted into outer space in the form of bright light.
Which is the same as the Sun. Moreover, small stars are ten times smaller in size than our luminary, and large ones exceed its parameters by one hundred and fifty times.
Often, in response to the question of what a star is, astronomers call these the main bodies located in the Universe. The thing is that they contain the main volume of luminous matter that can be found in outer space.
The stars in the sky that we can observe through a telescope are often surrounded by nebulae of various shapes. These new formations, which are clouds of gas and dust, can begin the process of compaction at any moment. At the same time, they will shrink into a ball-shaped figure and heat up to a significant temperature. When the thermal regime reaches six million degrees, thermonuclear interaction will begin, that is, a new celestial body will be formed.
Scientists have identified different types of stars. They are divided according to their mass and luminosity. It is also possible to divide according to the stages of the evolutionary process.
The class, which contains stars in which the emitted energy is balanced with the energy of thermonuclear reactions, divides them according to the type of glow into:
Blue;
White and blue;
White-yellow;
Red;
Orange.
The maximum temperature is observed in stars with a blue glow, the minimum - in red ones. Our Sun is a yellow luminary. Its age exceeds four and a half billion years. The core temperature, which scientists calculated, is 13.5 million K, and the corona temperature is 1.5 million K.
What is a giant star? This type of luminary includes fiery bodies with mass and diameters exceeding the Sun by several tens of thousands of times. Giants emitting a red glow are at a certain evolutionary stage. The diameter of a star increases by the time the hydrogen in its core is completely burned out. At the same time, the combustion temperature of the gases decreases and the red glow spreads over millions of kilometers. Giant stars include VV Cephei A, VY Canis Majoris, KW Sagittarius and many others.
There are also dwarfs among the heavenly bodies. Their diameter is much smaller than the size of our Sun. There are dwarfs:
White (cooling);
Yellow (similar to the Sun);
Brown (often considered as planets);
Red (relatively cold);
Black (finally cooled and lifeless).
There is also a type of variable stars. These luminaries are bodies that have changed their brilliance and development dynamics at least once in the entire history of observation. These include:
Rotating;
Pulsating;
Eruptive;
Other unstable, new, and hard-to-predict luminaries.
Such stars, which are represented mainly by bright blue and hypernovae, are very specific and little studied. Each of them is the result of the resistance of matter and the work of gravitational forces.
Stars are also considered to be one of the stages in the evolutionary process of celestial bodies. Such a body does not emit glow, but certain of its characteristics put it on a par with stars.
We can see the stars on a clear night. To us, they appear as twinkling tiny points of light in the sky. But have you ever wondered what stars are and what they are made of?
What are stars made of?
Stars are massive collections of very hot gas and plasma. The main components of the gas that make up a star are hydrogen and helium.
The gas does not scatter to the sides and does not evaporate due to its own gravity.
A star is like a kind of cosmic engine that produces heat and light. Inside the star there is a constant nuclear reaction - the conversion of hydrogen into helium, like a hydrogen bomb.
The sun is a star
The Sun is the closest star to Earth! It is designated as - G2 - yellow star.
75% of the matter in the Universe is hydrogen, and 23% is helium. These elements exist in giant cosmic dust clouds of cold molecular gas.
According to the current theory of star formation, stars are born as clusters in giant gas clouds.
The gas swirls through space in cosmic dust clouds called nebulae. Over time, gravity causes these clouds to condense. As they get smaller, the clouds spin faster due to conservation of angular momentum—the same principle that causes a spinning skater to speed up when she extends her arms.
Most of the mass collects in the center. The cloud's rapid rotation causes it to flatten into a protoplanetary disk. The cloud's gas heats up as it enters under its own gravity.
When the gas reaches a temperature of about 15 million degrees Celsius, hydrogen nuclei begin to fuse into helium nuclei, and a new star is born.
Young stars at this stage are called protostars. The protostar at the center of the cloud is heated by the gravitational collapse of hydrogen and helium and becomes increasingly hotter. As they develop, they accumulate mass from the clouds around them and become what are called main sequence stars.
How many stars are there?
Nobody knows how many stars there are. Our Universe probably contains more than 100 billion galaxies, and each of these galaxies may have more than 100 billion stars.
However, on a clear, dark night, the Earth's sky reveals to us no more than 3,000 stars that can be seen with the naked eye.
The stars are shining
Stars produce their own light and energy through a process called nuclear fusion. When this happens, a huge amount of energy is created, causing the star to heat up and shine. The luminosity of a star depends on the amount of energy produced by the star and how far from Earth it is.
Stars come in different sizes and colors. The color of stars depends on their temperature and size.
Hotter stars emit white or blue light, while cooler ones emit orange or red light.
Star sizes
The sizes of stars vary greatly. They are classified ranging from dwarfs to supergiants. Supergiants may have a radius a thousand times larger than our own sun.
The biggest and smallest stars
The most massive star is still a matter of scientific disagreement, but it is thought to be about 150 to 250 times the mass of the Sun.
The smallest possible star is about 75 times the mass of Jupiter. In other words, if you could find 74 more Jupiters and combine them together, you would get a star.
The stars are disappearing
Every star is not eternal. Over time, it disappears, but it takes millions and billions of years.
The greater the mass of a star, the shorter its lifespan. The most massive and hottest stars exhaust their energy supply within a few million years, while dwarf stars can continue to burn for many billions of years.
Closest star to Earth after the Sun
The next star after the Sun, which is closest to Earth, is Proxima Centauri. It is located about 39.9 trillion kilometers or 4.2 light years from Earth.
This means that its light reaches Earth in 4.2 years. Using the fastest spaceships, it will take about 75,000 years to reach it.
When I was six years old, for some reason I disliked kindergarten. And poor mother, instead of handing me over to the teacher with peace of mind, had to leave me with her high school niece. Probably, the young ego was annoying her. Another reason why the quite banal question “ what is a star“, I received a whole list of possible interpretations, I don’t see it.
What can be called a star
Everyone knows that a star is an astronomical object, like our sun. A ball of gas weighing billions of tons, with a diameter ranging from “slightly larger than a small planet” to “the entire solar system plus another couple thousand kilometers.” But this is not the only option. So, in the modern world the term “star” can be understood as:
- Heavenly body, in which nuclear decay processes occur, which causes glow and heat release.
- Popular among the people celebrity.
- Animals and plants characteristic shape.
- Phraseologism, which in a figurative sense is understood fate: “Born under a lucky star.”
- Synonym of words"happiness" and "love". "My star!" - this is how medieval romantics often addressed their loved ones.
- Geometric figure or heraldic sign.
Where does the word "star" come from?
In ancient times, when people still knew nothing about space or the shape of the Earth, each people explained differently, what is a star. This was reflected in the language:
- Russian word for "star" comes from the Old Slavic “gvězda”- “shining”, “giving light”.
- In English this is - "star" - hole(as you might guess, in ancient Saxon mythology the stars were considered holes in the heavenly canopy).
- In Turkish the same name sounds like "yıldız" and comes from the word “year”.
- The Sanskrit words for "star" and "shine" are designated by one hieroglyph: नक्षत्र.
- The Greek word familiar to us from the term “astronomy” "aster" came from ancient Mesopotamia, where the goddess of love Ashtoret was worshiped. Its symbol was... That's right! Morning Star.
The ancient Egyptians believed that the stars were souls of dead pharaohs, priests and other great people. Even some gods became stars: for example, God Osiris(or Sirius in Russian transcription), killed by his brother Seth.
Phoenicians imagined the sky as precious carpet, embroidered with luminous sequins. According to Greek myths, the gods turned heroes (as a reward) and criminals (on the contrary, as an edification) into constellations.
Star sizes
I have always been interested not only in what a star is, but also in what size it could be. Already at school I learned that our Sun is just a dwarf compared to some of the giants of the Milky Way. For example, the radius is not so large Rigel, the second largest object in the Orion constellation, 70 times the radius of the sun. And "alpha" Orion, a red supergiant Betelgeuse– 1000 times!
VY Canis Majoris, a red giant in the constellation of the same name, has a radius 2000 times greater than the Sun. For comparison, if he were our luminary, Saturn’s orbit would be exactly in the outer corona of this “baby”.
Why baby? Because, for example, the red supergiant Epsilon Aurigae is 2700 times larger than our star. Place it in the center of the Solar System - and it would cover it entirely, along with Pluto and the Kuiper asteroid belt, located on the border of the System.
Every time I look at the stars, I have one very interesting question. No, I don't think much about what's out there. Although, of course, this is also interesting. Most often I think about our ancestors - what did they think when they looked at the night sky? Just imagine - you live, for example, in 500 BC. e. As such, there was no astronomy then, and people did not have the slightest idea about the world order. How would you explain to yourself what these “luminaries” are above you? :)
In this story I would like to talk about what stars are made of.
How can you find out what stars are made of?
If you have never been interested in physics and astronomy, then it seems that this is impossible. After all, these luminaries are so far away that it is not possible to determine their composition. How can you tell from a small light in the sky what it consists of? It turns out that it is possible!
Similar studies are carried out on the basis studying the ability of atoms differently Ptake in the light at various frequencies. Thus, it is produced analysis of absorption and emission rates of stars, by which one can already judge the composition of the star.
As indicated in the picture above, such studies provide insight not only into the composition of stars, but also into other chemical and physical indicators, such as temperature and pressure.
What are stars made of?
All stars have roughly the same chemical composition, and the sun is no exception. So:
- The basis is always hydrogen. Its percentage is approx. 73%.
- In second place is gelth, its share is usually 25% . So, these two substances account for about 98% of the total chemical composition of stars.
- They also contain many heavy substances in much smaller percentages: oxygen, carbon, various metals, etc.
All these substances are not located diffusely in the stars, that is, there are certain laws according to which substances are located in a certain part. All heavy elements, especially metals are located in the center of the star - the core. On the periphery other, lighter substances are located (helium and hydrogen). However, since helium is heavier than hydrogen, it will also be located closer to the center of the star.