In our galaxy, and indeed in the entire Universe, there are a great many different celestial objects. In the night sky, we can observe them in the form of a huge number of flickering dots and spots surrounding us from all sides. But what celestial bodies are called stars and why do we see their glow?
What are stars?
A star is a very distant, bright and hot gigantic mass, consisting mainly of helium and hydrogen gases. Due to the huge pressure created inside the star, the nuclei of hydrogen atoms begin to collide with each other, starting a process called nuclear fusion. At the same time, celestial bodies - stars - emit an incredible amount of light, heat and energy.
The main element of the star is hydrogen. As a rule, it is three times more than helium in it. The amount of helium directly depends on the size and age of the object: the more it is, the older the star. All other elements make up only 2%, but it is they that help scientists accurately determine the composition, luminosity, temperature, color, size of the star, as well as how far the star can be from the Earth.
What color and size can stars be?
Yes, stars come in a variety of colors. Among them are red, orange, yellow and blue. Color can tell astronomers a lot, and it depends on the composition and temperature of the star. The hottest are blue and white, they can have temperatures above 50,000-60000 ° C. Such as our sun - yellow. They have a temperature of about 5000-6000 ° C. The coldest are the reds. They have a temperature of "only" 2000-3000 ° C.
They also vary in size. What celestial bodies are called supergiant stars? Those that reach a diameter of almost a billion kilometers. There are also neutron stars with a diameter of only 30 kilometers. For comparison: the super-giant star Betelgeuse is so large in size that astronomers can easily distinguish the outlines of its surface, despite the fact that it is about five hundred light-years distant from our planet. Betelgeuse is so huge that if the Sun in diameter were the same, its edge would easily reach Jupiter. But this is far from the largest star! Scientists to this day discover new supergiants, several times the size of this incredible object.
What do we know about the star closest to us?
A huge ball, consisting of red-hot plasma, located in the very center of our system, this is the star - the Sun. Astronomy allowed scientists to learn almost everything about this luminary, without whose energy life on Earth would have been impossible.
Its diameter reaches 1,400,000 kilometers, or 109 Earth diameters. Around it moves a lot of comets, dust, asteroids and dwarf planets, as well as eight planets that form our solar system.
The Sun was formed 4.5 billion years ago as a result of a giant explosion of one or more stars, after which a huge cloud consisting of dust and gas appeared. It is called the protosolar nebula. What celestial bodies are called stars and how they are formed, we have considered above, and on this basis, with accurate confidence, we can say that the Sun is the real star closest to planet Earth, which releases an incredible amount of nuclear energy and is the center in our solar system.
Conclusion
From time immemorial, the starry sky has attracted human eyes to itself. Using the best optical devices allows scientists not only to know what celestial bodies are called stars and planets, but also to look far into space, for many, many millions of light years, revealing more and more secrets contained in this amazing uncharted space called the Universe.