I’m not sure what TV show this was from, it might have been The Office or The Big Bang Theory, but in the show one character insulted another rather obnoxious character who was protesting how smart they were. The conversation went something like…
Him: “I’m smart. I’m intelligent.”
Her: “Oh, sure, you’re right at the top of the bell curve.”
For those of you not familiar with a bell curve, it describes how the normal distribution of “things” whatever they may be, tends to cluster around the average/mean. Most “stuff” is similar, with the exceptions being far less frequent. This is true when it comes to test scores, job incomes, or even something like the natural variations in a species of animal. “Things” tend to be the same.
No one likes to think of themselves as average, and yet the majority of us are clustered right around that mean. Scott Adams has a great cartoon that plays to this concept.
Being average isn’t so bad. We’re all average in one way or another, as there’s so many ways to measure ourselves.
I was chatting with a friend about stars and they made the point that the average distance between stars across the whole universe is about 4,000 light years, while the average within our galaxy is 4 light years or about 0.02 stars per cubic light-year, highlighting that there’s a whole lot of empty space out there between galaxies.
Look somewhere like a globular cluster or in the center of a galaxy, and the average is several stars per cubic light year. In these dense regions of a galaxy, stars are practically on top of each other, and the tremendous gravitational tidal forces produced can cause stars to be thrown out of the cluster and even out of the galaxy altogether.
The point being, if you look at all the stars in our galaxy, we’re right smack on the mean. We’re roughly the “same as others,” and that bodes well for the search for life beyond Earth.
Scientists even have a name for this, the Copernican principle, which states that Earth is not special or exceptional. We may think the Earth is, but that’s because we have a natural bias. Mediocrity might be bad in business, but in science, it is the only rational, logical assumption you can make. Out of the roughly two hundred billion stars in our galaxy, and the estimated forty billion planets surrounding those stars, Earth is probably quite mediocre. Certainly, in terms of our distance to other stars we are.
Given what we can observe, life should be quite abundant in our galaxy. Why haven’t we found life? Well, that’s a bit like asking 14th century sailors why they haven’t found the fabled Indies yet. Oh, sure, we can sail to England or to the islands of the Mediterranean, but sailing west to the Indies??? How preposterous! And yet now, of course, such a journey by sea or by plane seems quite rudimentary.
We will find life in outer space. It’s just a matter of time. How can I be so confident? Because we already know life can thrive in space. Earth is the perfect example, and Earth and her star appears to be quite mediocre.
We’re at the top of the bell curve, woo hoo!