It occurs to me that much of scientific progress, at least in the realm of astronomy and our understanding of the universe, since the enlightenment can be described as a regression of the importance of human beings relative to the universe. Of course, it used to be obvious that the Earth was at the center of the universe and everything revolves around us*. We were special.

But then Galileo and others came along and showed that the sun is the center of the universe and we are just one of a number of objects orbiting it. But our sun was special.

In the 1800s we finally learned that there is nothing special about the sun. It is just a relatively unremarkable star sitting on the limb of a much larger collection of stars known as our galaxy. But the galaxy was special.

In the early 1900s, Edwin Hubble proved that many of those splotches we see in the sky are not clouds of gas and dust within our galaxy, but are massive galaxies of their own, with their own stars, planets, and perhaps civilizations looking back.

This pattern can be expanded to the search for exoplanets. Forty years ago no one knew how many other planets there are in the galaxy. Some people thought many, some thought very few. The first known exoplanet was not confirmed until the early 1990s, and the discovery of more exoplanets kept trickling in after that

Still the question remained, is Earth special? Many of the planets found were massive gas giants or orbited so close to their sun that they could never sustain life. The flood gates burst open with the Kepler space telescope mission in the early 2010s which discovered thousands of planets. Extrapolating that data set leads to the conclusion that, on average, there are likely more planets than there are stars in the sky. Many are also rocky planets like our own.

We know that we neither occupy a special place in the solar system, nor is our planet particularly special. But the question remains, are we special? Are there other life forms out there or do we happen to live in a large quiet galaxy? I tend to think that the latter argument is simply a reflection of our own inflated self-worth. We are not special, and someday I think we will need to face that fact.

——–

*When reading about this topic my first thought was always, “how were these people soooo stupid?” but they did actually take some observational astronomy into account. One of the main defensible arguments for the geocentric model of the solar system was that the stars lacked any stellar parallax, i.e. the relative position of all the stars to each other did not change throughout the year as would be the case if the Earth was moving through a field of relatively close stars. Of course, we know today that the other stars are just unimaginably far away. There is some parallax, but the tools needed to actually measure it weren’t developed until the 1800s.