Galaxies are huge revolving cities of stars. Without a telescope, only three galaxies and part of our own Milky Way Galaxy can be observed from Earth. Two of them are called Magellanic Clouds.
This name they got in honor of the Portuguese navigator Fernand Magellan. When Magellan's ships sailed in the southern seas in 1519, crew members saw two dimly glowing galaxies in the sky. They brought news of this with them to Europe.
Closest galaxies to Earth
Galaxy Magellanic Clouds
The Magellanic Clouds really look like two small clouds - dim and solid. These two small galaxies revolve around the larger Milky Way. So the Magellanic Clouds are our closest neighbor. How small are these galaxies? One of them contains 15 billion suns, the other only about 5 billion. For comparison, we can say that in our Galaxy there are about 200 billion stars.
Galaxy Andromeda Nebula
The third galaxy that can be observed with the naked eye is the Andromeda Nebula. This is a spiral galaxy similar to the Milky Way. The Andromeda Nebula is 2.2 million light-years from us. A light year is the distance that light travels in one year, flying 300,000 kilometers per second. About 9.6 trillion kilometers are obtained in a year.
This means that the Andromeda nebula is at a distance of 2,112,000,000,000,000,000 kilometers, and that light takes 2.2 million years to get from the Andromeda nebula to the Earth, and it also follows that we see the galaxy as it was 2.2 million years on the backside.
When we look with the naked eye at the Andromeda nebula or the Magellanic Clouds, we do not see individual stars. Only a spot with dimly defined edges is visible, the aggregate light of millions and millions of suns. In addition to the three galaxies considered, in the night sky you can see part of the Milky Way. The powdery-white streak of stars crossing the sky is part of the disk of our Galaxy. The ancient Greeks believed that the white stripe was a trickle of milk from the breast of the goddess Hera. In Greek, the word "milk" will be "ha - la." This is where the word galaxy comes from.
Other galaxies, distinguishable only by a telescope, have very interesting and unusual names. There is a tiny galaxy Sculptor. In the sky there is a Dragon, Tongs, Leo 1 and Leo 2, Sextan, Pegasus, Wagon and Sombrero.
Galaxy names
True, there are so many galaxies (about 100 billion galaxies in the Universe) that there will probably not be enough names for everyone. Therefore, each galaxy has a letter - a digital designation. In the 18th century, the French astronomer Charles Monsieur compiled a list of undefined luminous celestial bodies. About 100 objects were listed, among them there were several galaxies. He assigned numbers to each object: M1, M2 and so on (so the Andromeda Nebula has serial number M31).
Later astronomers developed more extensive and detailed catalogs of galaxies and other space objects: constellations and nebulae. So many galaxies have only numbers in the New General Catalog or in the Directory Index.In these catalogs, the Andromeda nebula is listed under the number NGG224. The word "galaxy" comes from the Greek word "gala", which means milk.
