There are many galaxies that exist in the universe. However, central to the existence of the earth is the Milky Way Galaxy. The Milky Way is between 13 and 15 billion years old. It has 100 billion stars and a diameter of 100,000 light years. Within the Milky Way, there are two strong centers. The first one is the sun while the other is the galactic center. The galactic center is the source of the sun’s sun. It is the nucleus of the Milky Way. Galaxies may sometimes merge leading to the rapid formation of a star. Scientists predict that the Milky Way Galaxy is likely to combine with the Andromeda Galaxy to form the Milkomeda.
What Is the Galactic Center?
A galactic center is the rotational center of a galaxy. In the context of the earth’s Milky Way Galaxy, the galactic center is located within the Sagittarius constellation. It is 27,000 light years way from the earth and has a bulge of stars surrounding it. The stars in one parsec of the galactic center are 10 million in number. The stars are dominated by red giants and massive giants such as 100 OB. Interstellar dust covers the galactic center forming “smog” over it. Consequently, it becomes difficult to observe the galactic center using ordinary ultraviolet or soft X-ray wavelengths. To see the earth’s galactic center powerful gamma rays and hard X-rays are used. Besides the stars, the galactic center also has very high-density gas and high temperatures too. Additionally, a strong galactic wind and large amounts of hot plasma also exist.
The Mystery of the Galactic Center
The mystery is that the galactic center harbors a supermassive black hole. Supermassive black holes are formed by a combination of hundreds and thousands of tiny black holes within a span of time. Black holes form when original stars burn out and crash out of existence. The stars get compressed and form a central point called the “hole.” The black hole has so much gravitational force that any object that gets near it is pulled into it.
The supermassive black hole found in the Milky Way Galaxy is intriguing. It is about 4 millions times the size of the sun in mass. Typically, black holes are only 20 times larger than the sun. Also, even with the most powerful telescopes in the world, astronomers are unable to see this supermassive black hole. They can only ascertain its existence by its effect on the objects surrounding it. An evidence of its existence is the movement of the stars surrounding it in an elliptic motion as if they were circling a particular object. Astronomers have also noted strong radio waves around a point called Sagittarius A*. The supermassive black hole is believed to be located at this point.