Looking for the neighboring galaxy
In early 1781 a French astronomer and comet observer was named by Charles Messiah. He lists 103 terrestrial objects like comet, so that other comet observers do not mistake them as comets.
Because when the comet is close to the sun, its long tail or tail is visible. As a result, they are easily recognized. If you stay away from the sun, the tail becomes extinct. As a result, some observers mistakenly call them stars. During that time, he did such a wonderful job without the help of advanced equipment. Later, William Herschel, John Herschel, Louis Dreyer, etc., developed this list.
There were a lot of things in the list of Messi's in our galaxy Milky Way. However, many items on the list of Messi were out of Milky Way galaxy. One of them is Andromeda Galaxy. It is seen in the clear sky with empty eyes. Looks like a little foggy object.
In 964, Persian astronomer Abdur Rahman al-Sufi mentioned this in a book. In the book it was referred to as 'a small cloud'. The book is named Book of Fixed Stars. Later it was known that this cloud is another galaxy similar to our galaxy and it is also shaped like a spiral in our Milky Way. This is also the nearest neighbor of our galaxy.
Image: Abdur Rahman al-Sufi mentioned the Andromeda Galaxy in one of his books.
The nature of Nebula created by Messi, Herschel and Draire was of great debate in the late nineteenth century and early in the 20th century. Some thought that all of their astronomical objects in the constellation were located in our galaxy, and some thought that some of the objects in the list were outside our galaxy.
In 1755, German philosopher Emanuel Cunt had said that some galactic positions must certainly be outside our galaxy. He also said that some of these nebulae are shaped like circular discs. Because they are far away, they look dull.
In the 1920s and 1930s, this commentary ended with American astronomer Edwin Powell Hubble (1889-1953). He proved that most nebulae positions are outside of our galaxy. He implicitly proved that there was no respite for questioning or making any debate. Through him, a concept of a vast universe is conceived in humans. He made this groundbreaking proof of Nebula's red shirt.
During this time, a 100-inch telescope was completed in Mount Wilson near Los Angeles city of the United States. Scientist Edwin Hubble has the opportunity to use it at that time. Using the powerful telescopes, he revealed the nature of the Andromeda Galaxy for the first time. In this galaxy he found a spiral shape. Note that our own galaxy was not yet established.
He found some choking stars in parts of the Andromida spiral formation. There are some things in which brightness changes regularly over a specific time period. This type of star is called choking stars or variable star. They were, of course, discovered in our galaxy much earlier. They were called Cepheid Variable. Some of them were called Delta Cephei.
With the change of time, this kind of stars increases the brightness. If a person paints the image of brightness over time, then the shape of the image below will be created. A clear cycle of reducing brightness. A whole cycle can be called period or period.
Henrietta Swann Levitt and Harlow Shapley, two American astronomers, find a relation between the actual brightness and visible cycles of the Sephid tera. True brightness or intrinsic brightness is the main brightness of the seafide star. The true brilliance of science is also called 'Absolute Luminosity'.
The amount of light that radiates on any side of a sidereal substance is called the Absolute Luminosity. For some reason our stars do not recognize the original brightness in our eyes. The epitome luminosity that tells us that the sidereal objects of this kind are relatively bright in our eyes. The amount of light that comes from the stars in every single field on the telescope tells the proportions luminosity or visible brightness.
If the scientists Levit and Shepole find the relation between true brightness and visible brightness, they can be found in the chart, then a situation similar to the next image mentioned on another page can be found. The text is straightforward.
From the writing, it shows that if someone knows about the decrease in brightness of the chorus stars (period), then you can easily get the actual brightness out. Scientist Edwin Hubble found the existence of chronic stars in the Andromeda galaxy in this method. This method is called Levit-Shepoli relationship.
Now, if someone knows about the visible brightness and real brightness of any cosmic object, then the distance from the object can be determined. Because the visibility of brightness depends on the distance. The greater the distance of the object, the greater its brightness.
Using this method, Hubble concluded that the Andromeda Galaxy is 9 million light-years away. If there is so much distance, then its position must be outside of our galaxy. Because it is about 10 times away from the object that is far away from us. Note that our galaxy has a wide range of 80,000 to 1 million light years.
Later, in the late 1960s and early 1950s, German-born American astronomer Walter Bed (1893-1950) and other scientists showed that these types of chances are actually two types. They adhere to two types of rules. There are many chances of levit-shapely relations outside of coverage. Although Edwin Hubble, measuring the distance of endometrium through this relationship, the nature of the chaos star observed by stars and Levitt, is not exactly the same.
Hubble used wrong relationships with periods of time and brightness. For which he had wrong results as well. Later it is known that the actual distance of Andromeda Galaxy is two million light years, where Hubble said that the distance is 9 lakh light years. However, although Hubble's decision was wrong, Andromeda Nebula was outside of our galaxy.