Every morning and evening we witness the sunrise and the sunset in a colorful play. Luminous stars virtually hover over us like a parade during the night. We do not even notice the revolution of the earth around the sun and the specific movements of other planets and the stars in our galaxy while we remain busy with our daily lives. If we could take a closer look at the Milky Way which seems to be motionless, we would witness each amazing maneuver of the billions of stars and planets. The Milky Way galaxy is 200 thousand light years wide in the shape of a giant rotating disc and includes seven galactic arms in a spiral shape. It has been considered as a host to 100 billion stars like our sun. It is estimated that 125 billion more galaxies like the Milky Way exist in our universe. Just like how our sun is composed of planet moons, our galaxy also has smaller galaxy moons. These ten or so smaller galaxies revolve around the milky way as it rotates slowly like a machinery wheel. Sets of galaxies gaining distance from each other, planets revolving around stars, stars circling each other and stars orbiting galaxies ... what a glory to watch!
Galaxy and the Sun
The 21 cm long radio wave radiation emitted from the hydrogen gas within the dense dust and gas clouds of the arms of the galaxy enables us to know about the structure of the galaxy. This information led us to conclude that our galaxy is indeed not a solid object and displays a circular motion of 250 km per second. The Solar system is estimated to complete one revolution around the galaxy in approximately 200 million years. At this point the critical question that comes to mind is how a solar system orbit is maintained and protected during these journeys where the solar system bypasses the gravitation and effects of strong heavenly bodies without causing disruption and collisions. The Earth just won't become a habitable place only by considering planetary solutions. We may have to consider measures regarding our solar system and other galaxies, since the solar system has a very sensitive relation with the other heavenly systems in our galaxy.
The Sun's position in the Milky Way
Trillions of comets in the Milky Way galaxy fill the outer space and encompass the solar system in a globular fashion. One of the comet groups orbiting the solar system is called Oort or Opic-Oort cloud. A hundred billion comets is estimated to exist in the Oort cloud.
These comets follow the designated orbits until they deorbit with gravity of another strong heavenly body other that the sun. Stars and masses of the Milky Way constitute a globular center with spiral arms where these arms extend out of the center in the same galactic plane. There are a limited number of systems located in the space between these spiral galactic arms. In fact, this is where our solar system exists. In other words, it deserves attention that the sun does not reside in the dense centric part of the galactic arm Orion (Hunter) but exists in the nearby sparsely populated galactic mid space. The solar system that has been placed in the most appropriate position within the Milky Way also needs to be protected from possible dangers it may encounter (like crossing paths with dense spiral arms) during its journey around center of the Milky Way.
Scientist who study the place of our solar system in galactic maps particularly point out that we are far away and safe from the devastating effects of cosmic storms.
If the solar system did exist in the arm where stars are densely populated and near each other, gravitational forces could result in changes in planetary orbits. For instance, in the spiral arms of the galaxy, comets would easily deorbit and bombard the earth momentarily under the strong gravitational force of these arms. Yet remarkable measures have been taken to protect against this as well! One of them is the velocity value of the Sun. For example, in order to provide an effective communication, a satellite positioned in the earth orbit is given a speed equal to the one earth has for rotating around its axis. Our sun is given a suitable velocity to move with almost the same speed of galactic arms without intercepting each other, thus providing a safe passage. However this is not the case in 95% of the stars and the spiral arms in our galaxy unlike the one determined for our solar system. This is something to reflect and think about. Another measure that prevents the sun from intersecting with the spiral arms is that it has a circular orbit rather than in the form of an ellipse like stars of the same age. Also in this regard, we observe that our sun is given a special movement allowing Earth to become a habitable place for life. The All-Wise and All-Mighty Creator works the galaxies just like a giant machinery wheel with his established laws.
The stars in the spiral arms may in time get sucked into the inner parts of the structure, not being able to hold on to their position for a long period of time. This is also applicable for the sun. Divine measures also intervene here and leave the sun in the protective zone. The sun is located in the "galactic common rotational radius" where strong spiral arm effects do not exist. Furthermore, when Supernova explosions take place, giant star debris can reach a couple thousand light years away, enabling the sun not to be negatively affected from these explosions since it exists in the outer regions of the arms.
Cosmic dangers in the galactic center
The solar system is 28,000 light years away from galaxy center. If our galaxy is considered to be 200 thousand light years wide, one can say that we are relatively close to the center.
This location in the galaxy is distant enough to be protected from the negative effects that could arise from the galaxy center. What would happen if the solar system was closer?
In this case we would constantly be exposed to dangerous gamma, X-ray, and cosmic radiations, therefore no life on Earth! Not to mention the black hole in the galaxy center which has a mass 3 million times as much as the sun. If the sun were to exist near the black hole, life on earth would again be negatively affected from the strong gravity of it. The extraordinary measures that have been taken for our solar system, the sensitive adjustments that are put in place, and the maintenance of such balance and complexity all displays a perfect science and a Divine power in the background. All these events demonstrate clearly that no single event of randomness and chaos exists in the universe. The most complicated and sensitive tasks are resolved in the best possible way, therefore revealing a perfect organization. We see this perfect organization between the Milky Way, the solar system and the earth!
Mishurov, Y.N. and L.A. Zenina. 1999. Yes, The Sun is Located Near the Corotation Circle. Astronomy & Astrophsica 341: s. 81–85.