There will be a gigantic collision that will involve our home, but none of us will be alive to witness it. When all is said and done, there will be a giant collection of stars. The Andromeda Galaxy and our own Milky Way Galaxy are expected to collide 3,750,000,000 years from now.
The Andromeda Galaxy has long been an object of fascination to observers of the sky. If you live in the Northern Hemisphere, you can find the Andromeda by locating the Cassiopeia constellation. You may need a star chart for this. First locate the distinctive “W” shape in the sky. Use the right “line” of the “W” as a sort of pointer arrow. Go about three heights of the “W” in the direction of the pointer arrow and your field of vision will be in the neighborhood of the Andromeda. If you have brought along a binoculars, you will be able to spot what looks like a small elongated puff of smoke. The sky must be dark, no full Moon, no city lights, for this observation. If you know how to read star charts, you will find Andromeda much more quickly.
The first known description of the Andromeda in history was by the Persian astronomer Abd al-Rahman al-Sufi, who described it a a small cloud in his *Book of Fixed Stars in the year 964. In December of 1612, the German astronomer Simon Marius noted the object as the Andromeda Nebula. In 1764, the French astronomer Charles Messier catalogued the Andromeda Nebula as object M31 according to his classification and naming system. Prior to the 20th century, the Andromeda was thought to be a nebula within our own Galaxy. For instance, in 1785, William Herschel believed the Andromeda was the “nearest of all the great nebulae”.
The first telescopic photographs of M31 were taken by the English astronomer Isaac Roberts in 1887. The image showed the spiral shape of the nebula to be seen for the first time. Roberts incorrectly guessed that the Andromeda nebula and other nebulae were young solar systems in the process of formation. The spirals were thought to be coalescing into planets.
American astronomer Heber Curtis discovered a nova inside of the Andromeda. By comparing it with other novae, he believed that there were other massive collections of stars. In 1917, Curtis proposed the “Island Universes” hypothesis. The hypothesis states that spiral nebulae are actually independent galaxies.
In 1922, Estonian astronomer Ernst Öpik also theorized that the nebula was a far away object and was not a portion of the Milky Way Galaxy. His observation appeared to support Curtis’ “Island Universes” idea.
Confirmation of the “Island Universes” hypothesis snapped into place in 1925. American astronomer, Edwin Hubble, gathered more evidence
about the nature of the Andromeda nebula and others. He assembled previous work of earlier astronomers, like fellow American Vesto Slipher, with his own findings to verify that many nebulae are actually independent galaxies that exist far away from our own Milky Way and from each other.
Hubble had been at the right places at the right time. As he completed his doctorate work, the young astronomer was invited by the founder of the Mount Wilson Observatory in Pasadena, California, George Ellery Hale, to join the observatory staff. Unfortunately, the invitation came as Hubble finished his thesis at the same time as the entry of the United States into world war in 1917. Hubble joined the Army, but didn’t see action. At the conclusion of the Great War, he went immediately to the Mount Wilson Observatory and introduced himself.
One cold October night in 1923, Hubble saw the flare of what he thought was a super nova in the Andromeda nebula. During the next year’s time, Hubble studied the phenomenon. The star turned out to be a Cephed star, a variable star used to determine distance. Hubble calculated the distance of the star within the nebula and determined that it was 1,000,000 light years away from Earth. This distance placed the Andromeda far away from the Milky Way.
In November of 1924, Hubble’s observations helped him conclude that the Andromeda contained at least millions of stars and was, itself a galaxy similar to the Milky Way. The “Island Universes” hypothesis was verified. Because of Hubble’s studies, the area of the known Universe expanded. In effect, Hubble had “discovered” the Cosmos.
Science writers at the New York Times understood the importance of this event. On November 23, 1924 the newspaper published a story with the lead sentence, “Finds spiral nebulae are stellar systems. Doctor Hubbel [sic] confirms view that they are ‘island universes’ similar to our own.”
In 1929, Hubble determined another landmark fact. He had begun classifying all the known nebulae and was keeping track of all their distances from Earth and from each other. He also kept track of their velocities and direction of travel by observing their “red shift”. He determined that the galaxies all appear to be racing away from each other. He noted that the speed increased in proportion to their distances from Earth. This phenomenon gave the appearance that we live in an expanding Universe. This relationship has come to be called “Hubble’s Law”.
The discoveries about the Andromeda Galaxy and many other breakthroughs have expanded, not only the known Universe, but the fields of science and cosmology.
Edwin Hubble died on September 28, 1953 in San Marino, California. He left behind a legacy of many findings and the most commonly used system of classifying galaxies. His arrangement is known as the “Hubble Sequence”. He was further honored when the orbiting telescope bearing his name, was placed into orbit around the Earth.
We now know that the Andromeda nebula is really a Galaxy. M31 is much larger than our own Galaxy. We have also learned that there are countless billions of Galaxies populating the known Universe.
The Blue Jay of Happiness is astonished by a quote from Dr. Neil deGrasse Tyson. “There are as many atoms in a single molecule of your DNA as there are stars in the typical galaxy. We are, each of us, a little Universe.”