Yes we are. Every person you have met or will meet is an immigrant. This is not about your parents arriving here from somewhere else, or your grandparents, or even your ancestors going back 10,000 years or more. Every person living or that has lived on this planet (or solar system) is alien to the Milky Way galaxy.
An outrageous statement? Not if you examine closely our origins. The star that we affectionately call Ol Sol was once part of very small galaxy, a diminutive neighbor to the majestic Milky Way. Our Sun, ensconced in that cozy miniature galaxy surrounded by a number of siblings, was just sputtering into existence several billion years ago. What a proud little galaxy it must to have been. Not very well organized. Just a scattering of average sized young stars. But, it had a grand secret – a plan for creating living things. This quaint collection of stars barely able to call itself a galaxy recognized that at least one of its terrestrial charges had a most rare opportunity for producing plants and animals in many forms, leading perhaps to the development of intelligent life.
The Milky Way is big. Not the biggest, but clearly it can be classified as among the big. A galaxy can be called big when it encompasses billions and billions of stars, plus other objects, that stretch many light years across space. (If you want an accurate count, say it has a bigllion stars.) It is known that a galaxy grows from a barely distinguishable knot of stars to a super size by two means. First, it makes new stars, generation after generation. Second, after it has attained a certain total mass, its gravitational attraction begins to act on other galaxies within reach, large and small. The large galaxy entices others nearby, especially the smaller ones, into joining its larger grouping. Most low mass galaxies are unable to resist. As these approach and enter the larger assemblage, they are stripped of their stars. Each star, now just one among a ‘bigllion’, is assigned a nondescript place of orbit within the big galaxy. A galaxy gets to be big by repeating many times this process of absorption of smaller units.
That’s what happened to our progenitor galaxy several billion years ago. While it was still intact it looked over at the dazzling lights of the huge galaxy we call the Milky Way. So organized. So magnificent. So attractive. Great things must be happening there. So irresistible! And, there was this – our home galaxy’s plan for creating Life had hit snag. The basic chemical compounds had been assembled on several of its planets, carbon compounds, even a few amino acids. But, the physical conditions were just not right. For example, the plan called for liquid water. There was plenty of H2O, except that on the various planets it was either hot steam or frozen solid, and almost always mixed with the wrong chemicals. Then there were the missing elements. Our little galaxy had gleaned from space a few precious components during its travels. Still, it lacked certain heavier elements. These could only be produced by super novas (exploding giant stars), rare in a small galaxy. Over in the Milky Way these chemicals were abundant.
Life! Was it worth the loss of independence? Loss of self identity for this small galaxy? Indeed, yes! For it brought into being something very uncommon, perhaps unknown in that much greater galaxy – self replicating living organisms. To complete its mission this toddler of a galaxy had to sacrifice its very self and wholeness. Scientists assume that the spontaneous emergence of living things requires a vast network of opportunities and a high degree of complexity, both available for a long span of time. Not so? Well, our little galaxy and its special star did it in record time. The Milky Way does not deserve credit for this accomplishment. As far as is known, the Milky Way has not produced advanced life forms before now. Indeed, during its early turbulent times this now colossal galaxy would have snuffed out any attempts at life with super novas. Instead of turning our detectors for intelligence onto the giant galaxies, perhaps we should be looking at those small mom and pop galaxies out there, alone in dark space, dreaming big dreams.
You may have noticed the references in this article to our small parent galaxy as ‘it’. It does not have a name because scientists feel ‘it’ has lost all identity as a galaxy. Due to the angle of entry into the Milky Way, our star along with the remnants of that lost galaxy obit the giant Milky Way in a way that takes this motley group of survivors a few light years above the plane of the galaxy and then a few light years below, while shuttling between the Sagittarius Arm and Perseus Arm of the M.W. galaxy. Why is it other captive dwarf galaxies have been given names, e.g., Canis Major and Complex H., Sagittarius and UMajor, and even Boo?
After nearly five billion years we may no longer think of ourselves as immigrants; still, our history endures. Like all new generation families we have little or no recollection of the ‘old country’. Even so, doesn’t that little galaxy that gave us life deserve our appreciation? Come on folks, People of Earth, let’s give that unknown and forgotten galaxy a name. (Examples, Atlantis, or Salvitar, or Maia.)
By Charles Scott, aka Kopernik2