On a clear, moonless night, you can look up and see the Milky Way. Actually, we are in the Milky Way, a spiral galaxy of 200 billion stars one of which is our Sun. We are located in a spiral arm of that galaxy 26,000 light-years from its center. Our location seems to indicate many galactic coincidences.
At the center of the Milky Way (and perhaps all galaxies), there’s a black hole sending out lethal radiation to a distance of 20,000 light-years. Farther out than 26,000 light-years from the center, heavy elements that are vital to our existence and survival are scarce. We are in what astronomers call the “galactic habitable zone.”
Spiral galaxies rotate, and we are near the co-rotation spot where our solar system moves at almost the same rate as the spiral arm we are in. If we were in precisely the co-rotation spot, we would experience gravitational “kicks” which could send us out of the habitable zone. If we were far away from the co-rotation spot, we would fall out of the arm and be subjected to deadly radiation.
In the vast majority of spiral galaxies, the habitable zone and co-rotation spot do not overlap. Most other spiral galaxies are not as stable as ours. Most galaxies are not spiral galaxies and would not have a stable location for advanced life.
Furthermore, galaxies exist in clusters, and our cluster called the “Local Group” has fewer, smaller, and more spread-out galaxies than nearly all other clusters. Most galaxies are in dense clusters with giant or supergiant galaxies which create deadly radiation and gravitational distortion making advanced life impossible.
These are only a few of the many factors that “just happen to be” true of the place where we live. Are these just galactic coincidences? Some say it’s all accidental. We say it’s a grand design by a Master Designer. The next time you look up at the Milky Way, thank God that we are precisely where we are.
–Roland Earnst © 2018