What is a star?

What is going on in the sky?

When you look at the night sky, you see different objects. For example, you may see the moon. Sometimes you may see bright spots that do not shine like stars. These are the bright spots of the planets. If you have a telescope or binoculars, you can also see some of the planets around them, and from their attack you can probably see the four brighter moons of Jupiter.

 

But on most dark, clear nights, you only see the stars. Stars are bright spots that twinkle. There are thousands of stars in our field of vision, and the darker the sky, the more stars you will see. There are millions of stars that are out of our sight. All the stars except the sun are very far from us and are outside our solar system. The nearest star, Proxima Centauri, is 4.2 light-years away.

When you look closely at the sky, you will see that some stars are brighter, some are dimmer, some look blue, some are white, and some look pale yellow or red.

There are many types of cosmic stars, which we will discuss in another article.

We sunbathe under the light of a star, the sun. The sun is different from the planets in our solar system. Planets are much smaller than the Sun and are usually made of either rock (like Earth and Mars) or cold gases (like Jupiter and Saturn).

The sun, like other stars in the Korean universe, is huge, bright, and hot, made up of burning gases held together by gravity. The sun, along with 400 billion other stars, is located in the Milky Way galaxy. The principle governing stars is the same: stars produce light and heat by fusing atoms in their nuclei. This is the secret of the life of the stars.

In the case of the sun, this fusion means that hydrogen atoms form helium atoms under extreme heat and pressure. The collision of hydrogen atoms produces heat and light. This is called stellar nuclear fusion, and it is the source of all the elements in the universe that weigh more than hydrogen and helium. As a result, everything we see, even ourselves, is made up of atoms of material inside the star.

Now how does this synthesis of a star form and during which the star does not explode? The answer is: hydrostatic balance. The hydrostatic equilibrium is the equilibrium of gravitational mass of the star (which draws gases in) with the help of external pressure due to heat and light (radiation pressure) (which occurs inside the nucleus due to nuclear fusion).

This fusion is a natural process and requires large amounts of energy to initiate fusion reactions to balance the gravitational force of the star. The core of a star needs temperatures in excess of 10 million degrees Celsius to initiate hydrogen fusion. The temperature of our solar center is 15 million degrees Celsius.

A star that uses hydrogen to produce helium is called a main-sequence star. When all of the star’s hydrogen is consumed as a result of its conversion to helium, the nucleus contracts (due to insufficient external pressure of the radiation to balance gravity). In this case, the core temperature increases due to compression and helium is converted to carbon by fusion. In this case, the star becomes a red giant.

The next stage in a star’s life depends on its mass. A low-mass star like the Sun has a different fate than heavier stars. In low-mass stars, the outer layers explode at this stage, forming a star nebula centered on a white dwarf.

However, massive stars explode to form supernovae. In this way, the constituents of the star are scattered in space. The most familiar example of a nebula is the Crab Nebula in the constellation Taurus. The core of the main star becomes either a black hole or a black hole when the star turns into a supernova or a neutron star.

Stars are scattered in billions of galaxies across the universe and play an important role in the evolution of the universe.