As was true of many scientific advances, what was done with the heliocentric theory was no fault of Nicolas Copernicus.  Like most pre-modern scientists, Copernicus was a clergyman, fully in accord with Church and its teachings, secure in the Christian worldview of man's special status in the universe.

Copernicus would never have come up with the "Copernican principle," and it's highly likely he would not have approved.

The Copernican principle is derived from one of the major findings of Copernicus's heliocentric theory: the dethronement of the earth from its place in the center of the solar system (and, presumably, the universe) that it had held in the Ptolemaic system to a secondary spot as one of a number of planets orbiting the sun.  From there, utilizing a number of leaps in logic that need not concern us, astronomers derived the Copernican principle: that there is absolutely nothing special about the sun, the earth, or the species that abides on it.  The sun was a G-class star like any of the uncounted billions, the earth was a commonplace world doubtless much like countless others, and the humans were simply products of mechanistic evolution no doubt commonplace across the cosmos.

The revolution brought about by orbital projects such as the Hubble, Kepler, and James Webb telescopes has overturned much the science was absolutely certain of.  It has recently become apparent that the Webb telescope has thoroughly trashed the Big Bang theory, to the despair of cosmologists and sitcom producers.  Either the universe is far, far older than what was previously believed, or there was no big bang at all.  (Those of us who were paying attention knew that this was coming, one way or another.  The introduction of inflation theory in 1980s to explain flaws in the original theory was the equivalent of a Ptolemaic epicycle — always the sign of a failing theory.)  Some serious thinking in cosmological circles.

What concerns us is a bit closer to home — namely, the planetary systems.  Hubble and Kepler have between them discovered 5,400+ planets circling nearby stars.  These discoveries too have kicked over some doctrinal apple carts.

For centuries, it has been assumed that the solar system was an average example, and that any system of planets discovered around other stars would be much like it, with a few wild variations thrown in for spice, maybe.  Hubble and Kepler, in much the same style as their namesakes, have wrecked that assumption.  As of now, our solar system looks next to nothing like anything else we've discovered.

To begin with, there are two major types of planets, common around other suns, that simply don't exist here — super-Earths and super-Jovians.  Super-Earths are, like the earth itself, rocky terrestrials but are 3 to 10 times the size of earth itself, with corresponding increases in mass and surface gravitation.  Super-Jovians (or super-Jupiters) are gas giants, like those in the outer reaches of our system, but two to ten times the size of Jupiter, our reigning planetary monarch.

But the other, and more serious factor involves the arrangement of exosolar planets.  Among the thousands of systems now discovered, it has become clear that the array of planets circling Sol is a rarity nearing the point of being unique.

Astronomers have settled (for the time being, anyway) on four distinct types of planetary systems.  The first is the Similar class, which, as you might guess, consists of planets that are roughly the same size.  This is the most common type of system.  The second is the Anti-ordered system, which consists of giant planets close in and smaller, terrestrial types farther out.  The third class is the Mixed, with giants and terrestrials orbiting at random distances.  The last, and the rarest, is the Ordered class, with small terrestrials close in and giants farther out.

That last is what we've got.  And it's the rarest class of planetary system by quite a margin.  In fact, up until now, not a single system duplicating ours has been detected (although this may be explained by technical limitations — it's difficult to detect small terrestrial bodies close to a sun).  All the same, we have to come to terms with the fact that most solar systems are wildly different than the one we're familiar with. 

We also need to think about what that means.  We don't know — at least not yet.  But one thing we can conclude is that our home system has resumed its spot as a special place in the universe.

I don't think Copernicus would mind that at all. 

Image: Public domain.