The galaxies of the universe They are huge accumulations of stars, gases and dust.
In the Universe there are hundreds of billions of galaxies. Each one can be made up of hundreds of billions of stars, nebulas, black holes and other stars.
In the center of the galaxies is where more stars are concentrated.
All bodies that are part of a galaxy move because of the attraction between them due to the effect of gravity, which Newton defined as universal gravitation. In general there is, in addition, a much wider movement that makes everything together revolve around the center.
Here is a list of the galaxies that we have more "close":
|Neighboring galaxies||Distance (Light years)|
|NGC 221 (M32)||2.100.000|
|The Triangle (M33)||2.700.000|
Sizes and shapes of galaxies
There are huge galaxies like Andromeda, or small ones like its neighbor M32. They are in the form of a globe, lens, flat, elliptical, spirals (like ours) or irregular shapes. The galaxies group together forming "clusters of galaxies."
The nearest big galaxy is Andromeda.
It can be seen with the naked eye and looks like a bright spot of foggy appearance. Arab astronomers had already observed it. It is currently known as M31. It is about 2,200,000 light years from us. It's twice as big as the Milky Way.
Galaxies have an origin and evolution
The first galaxies began to form about 1 billion years after the Big Bang. The stars that form them also have a birth, an evolution and a death.
The Sun, for example, is a star that was formed by accumulation of materials that came from previous, dead stars.
Many galaxy nuclei emit strong radiation, which indicates the probable presence of a black hole.
The movements of the galaxies sometimes cause violent shocks. But, in general, galaxies move away from each other, like dots drawn on the surface of an inflating balloon.
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|The galaxies||Classes of Galaxies|