In the night sky we see many stars, the stars together are called galaxies, and the number of galaxies is 100 billion, there are 100 billion stars in each galaxy. And the three galaxies together are called super clusters, and in one of them we have a galaxy called the Milky Way. Our nearest galaxy is Andromeda.
Stars have their own light and heat. The sun is a star because it has its own light and heat. The sun gives us light and heat, that's why we survive.The sun is the closest star to us.
formed by Gas, it was first a scattered gas, then by the force of gravity, the gas condenses in one place and forms a spherical shape called nebulae.And they produce light and heat, they have their own fuel. Hydrogen is converted to helium in the process of nuclear fusion and it looks like plasma.
When all of the Stars run out of fuel, the Stars become bigger and turn red. This process is called the Red Giant.The Red Giant has two conditions.
1) White Dwarf:
When the Stars run out of fuel 95% then it's called White Dwarf, this is the last stage of the Stars where they can be illuminated for the last time. This condition is called a fossil star. And when 100% of the fuel is gone, it is called a black dwarf. These are just the garbage of the universe, these stars are smaller than the sun.
It is bigger than the sun, it is also called an exploding star. Four types were created after the super nowa exploded.
This is the largest part of the super nowa.It has no plus or minus. Its rotation is very slow.
It is smaller than a neutron star and its rotational speed is very high.
It is smaller than Pulsar and its rotational speed is much higher.
(iv) Black Hole:
It has a very high density and a lot of weight, so it cannot penetrate light,So light cannot be reflected, it is called black hole. Its rotation is much higher, If this black hole collides too hard with a star or a planet, that planet will be destroyed. If a meteor comes towards the earth, it can be prevented by a missile, but if a black hole comes, it cannot be prevented because the density of the black hole is very high.
Colour of Star's:
The color of the star has been adjusted depending on its temperature।
(iii) Blue :
high temperature. Our closer star is the sun. The second is the proxima scentury. Third is the cirus or dog star. Countless twinkling stars in the night sky are similar to the sun. But we don't feel their heat or light, and they look so tiny because they are very very far from us.
Celestial body :
the sun, the moon and all those objects shining in the night sky are called celestial bodies. Some celestial bodies are very big and hot . They are made up of gases. They have there own heat and light.