Copernicus, Farewell!

Nicolaus Copernicus is often credited with starting the Scientific Revolution with his On the Revolutions of the Celestial Spheres. In it, he argued that the earth was not the center of the universe and in fact revolved around the sun. It began a trend in which successive scientific discoveries moved the earth further and further away from any central location in the universe, and closer and closer to mediocrity. This trend established itself in scientific opinion and, under the name The Copernican Principle, became a sort of doctrine for scientists. It is the humble blogger's contention, however, that the Copernican trend has reversed itself, most decisively, and that it is time to stop invoking it in astronomical and exobiological discussions. It is time, in other words, to say farewell to Copernicus.

This will be difficult for many, who seem to have a very firm fondness for the principle. The earth, say men such as Neil DeGrasse Tyson, is an unremarkable planet orbiting an unremarkable star in an unremarkable galaxy in an unremarkable part of the universe. There is nothing special about our circumstances and we can, therefore, expect to be an unremarkable species in this sea of mediocrity. Carl Sagan went so far as to estimate that as many as a million other intelligent species inhabit our galaxy alone.

And yet, it seems to your humble blogger that such talk flies in the face of more recent trends in science. That learned men of the sort mentioned above could still be preaching Copernicus in light of things more recently discovered is a testament to the unshakable doctrine that the Copernican Principle has become. That the earth is special, and in a special place, is becoming more and more apparent.

The universe in which we live is so finely balanced to support life that any suggestion of luck or coincidence should be dismissed out of hand. The fine tuning is such that to have arrived at it by chance would be far more remarkable than to thrice win a state lottery on successive tickets. It is not our purpose here to argue that a deity must have created the universe for it to be so finely tuned, nor to contend that we live in but one universe of sextillions and sextillions in the "multiverse" so that a stable universe where galaxies and stars form would eventually emerge. Our purpose here is merely to note that in either case we live in a very special universe.

There are good reasons to believe that our galaxy, a spiral galaxy, is a special kind of galaxy. Other types of galaxies, at least as far as our current understanding goes, are probably poor candidates for life. Indeed, not even all spiral galaxies are necessarily hospitable to the evolution of life and intelligent species.

Inside our own Milky Way Galaxy we appear to be located in a tract of prime real estate. We are far from the galactic center where the density of star distribution would make the evolution of animal life unlikely due to the dangers posed by other stars. But we are also distant from the outer edge where stars are unlikely to have the heavier elements in enough abundance to form larger planets.

Even our orbit around the galactic center seems to be ideal, leaving us generally isolated but taking us every so often through a spiral arm and its more densely packed stars. While continuous existence in a densely populated stellar neighborhood seems inimical to animal life and intelligence, there are some scientists who believe that an occasional flirtation with disaster actually propels evolution forward. It has been calculated that the periodic mass extinctions that our planet has experienced coincide with times when the sun passed through a spiral arm, and each time life adapted new and better forms.

Our solar system itself seems special too. On Youtube one can find the aforementioned Neil DeGrasse Tyson claiming that our star is ordinary, but this is demonstrably untrue. Our sun is larger than approximately 95% of the other stars in the galaxy, but not so large that it will burn out in a few hundred million years, or sooner, and thus die before advanced life can evolve on one of its planets. It is higher in metal content than the vast majority of other stars. Its planets have stable, nearly circular orbits, something that seems to be rare if the other systems so far discovered are any indication.

And our home planet seems to be well tuned for life. There are enough radioactive elements in the core to generate enough heat for plate tectonics, and enough iron to generate a protective magnetic field. There is enough water to lubricate the surface so that the subduction zones and volcanoes can continually recycle the planet's carbon, but not so much water that continents never break the surface. There is enough gravity to hold an atmosphere, but not too much gravity either.

The ways in which our place in the universe is special abound. There are certainly myriad other unique aspects not discussed here. Just as the universe itself is finely tuned to allow for life, so too seem to be the characteristics of our own celestial neighborhood. If this truly is the case, and the evidence points in this direction, we should not be surprised to find few other intelligent species out there. The possibility of complete isolation should not be discounted. So well established is the Copernican Principle that perfectly respectable scientists today go around invoking it, but facts seem to be pointing a different direction.

Copernicus, for centuries you have tried to convince us that we were mediocre. Now we are on to your little game. As our understanding of the universe grows, our appreciation of our place in it increases. We are indeed special; the Church, however wrong its reasons, was correct in this. Not only are we special, we are more special than we ever realized we possibly could be. Your facts were true, but the interpretation that bears your name is poor. Let us read to your Principle its Last Rites. Farewell!