The Andromeda Galaxy

Andromeda GalaxyThe size of universe is unlimited, till the 21st century the size of the universe is unknown and as the studies suggest our universe is expanding. In this large universe there are numbers of stars, planets, moons, asteroids and meteoroids and other heavenly bodies. There are billions and trillions of galaxy present in the universe and where our earth is a very tiny dot in it. Our earth lies in the Milky Way galaxy. In the milky way galaxy there are number of start planets and stars presents which it still uncountable to us. The nearest galaxy from the Milky Way galaxy is Andromeda Galaxy. Andromeda Galaxy is our neighbor. The Andromeda galaxy is also called a spiral galaxy which is nearly approximately about 2.5 million light years from the earth in constellation Andromeda. One light year mean time taken to travel for light in one year or 1 light year = 1 year. Similarly 2.5 million light year means if anything travels as the speed of light than it takes 2.5 million years to reach there which is impossible till now. Andromeda Galaxy is also called Messier 31, M31 or NGC 225 and which is also referred to Great Andromeda Nebula. As I have already mentioned that Andromeda is spiral galaxy to our Milky Way galaxy and is also nearest but it is not the closest galaxy overall.

Andromeda GalaxyName of the galaxy is named as the Andromeda because it lies in the Andromeda constellation and which is named after a mythological princess Andromeda. Andromeda is the largest galaxy in the universe which consist of Triangulum Galaxy and other 30 smaller galaxies. As the galaxy is largest but may not be most massive. According to the recent study it is found that in Milky Way galaxy there are lots of dark matter and which may be the most massive in grouping. The observation made by the Spitzer Space Telescope in the year 2006 it is found that M31 possesses one trillion (1012 ) stars but in our galaxy it is estimated to be about 200 to 400 billion.

According to the study the masses of the Andromeda Galaxy is estimated to be about 7.1 x 1011 solar masses. It is also estimated that the two galaxies Milky Way galaxy and Andromeda Galaxy will get collide in 4.5 billion years.

Andromeda Galaxy can be viewed by our naked eye on moonless night. Andromeda Galaxy is one of the brightest Messier objects at an apparent magnitude of 3.4. The galaxy appears to be more than six times wider than that of the full moon when photographed from the large telescope, but while viewing through the binoculars and smaller only the central region of the galaxy can be viewed with our naked eyes.

Nearly around 964 a Persian astronomer Abd al- Rahman al-Sufi had written exciting lines about the chained constellation in his Book of Fixed Stars. This book describes the Andromeda Galaxy as a small cloud. A German Astronomer Simon Marius had given the first description about the object based on the telescopic observation in the year 1612. In the year 1764 Charles Messier catalogued it as M31 and incorrectly credited Marius as the discoverer, unacquainted of Al Sufi’s earlier work. The faint reddish hue in core region of M31 was noted by the astronomer William Herschel in the year 1785. During the time he believed that this is to be nearest of all great nebulae which is based on magnitude and the color of nebula, he also incorrectly guessed that it was no more than 2000 times the distance of the Sirius.

Andromeda GalaxyIn the year 1864 it is observed that the spectrum of M31 & also noted that it is differed from the gaseous nebula by William Huggins. Spectra of M31 displayed a continuum of frequencies, superimposed with the dark absorption lines which help to identify chemical composition of an object. The nebula of Andromeda was as similar as the spectra of the individual star & from that it was figure out that the M31 had stellar nature. The supernova called as S Andromedae was seen in the M31 in the year 1885, which was only one observed in that galaxy. During the time M31 was assumed to be the nearby object, therefore the cause was thought to be much less luminous and unrelated event known as Nova and was named accordingly Nova 1885.

In the year 1887 Isaac Robert took the first photograph of M31from his personal observatory at Sussex, England. This was the first time for the spiral structure of galaxy to be seen. During the time the object was still considered as the nebula within our Galaxy. And the William Robert mistakenly believed that the M31 & the similar spiral nebulae were in fact solar systems being formed, with satellite nascent planet. In the year 1912, radial velocity of the object was measured by Vesto Slipher at Lowell Observatory by using the spectroscopy. This was measured with respect to solar system. And the output result was very largest velocity, at 300 km/sec moving in the directions of Sun.


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