What are the galaxies of the universe | Earth, Solar System and Universe.

Galaxies are huge clusters of stars, gas and dust.
There are hundreds of billions of galaxies in the universe. Each one can be formed by hundreds of billions of stars and other stars.
In the center of the Galaxy is where more stars are concentrated.
All the bodies that are part of a Galaxy move because of the attraction of the others due to the force of gravity. In general there are, in addition, a much broader movement that causes all together to rotate around the Center.
Here is a list of galaxies that we have "closer":

Neighboring galaxies Distance (years light)
Magellanic Clouds 200,000
The Dragon 300,000
Ursa minor 300,000
The sculptor 300,000
The stove 400,000
Leo 700,000
NGC 6822 1,700,000
NGC 221 (M32) 2.100.000
Andromeda (M31) 2.200.000
The triangle (M33) 2,700,000

Sizes and shapes of galaxies

There are huge as Andromeda, or small as M32 neighboring galaxies. They exist in globe, lens shape, flat, elliptical, spiral (like ours) or irregular shapes. The galaxies are grouped together forming "clusters of galaxies".
The nearest large Galaxy is the Andromeda.
You can see with the naked eye and seems a bright spot of hazy appearance. Arab astronomers had already seen it. Currently it is known under the name M31. It is about 2,200,000 years light from us. It is twice as large as the Milky way.

Galaxies have an origin and evolution

The first galaxies started to form one billion years after the Big Bang. The stars that formed them have a birth, life and death.
The Sun, for example, is a star formed by accumulation of materials that came from above, dead stars.
Many nuclei of galaxies emit strong radiation, which indicates the likely presence of a black hole.
The movements of galaxies provoke sometimes violent clashes. But, in general, the galaxies are
they drive away from the other, as drawn on the surface of a balloon that is inflated.
Published for educational purposes