Comparisons

Whenever I’m thinking about something outside of the realm of human experience, like an unimaginably long amount of time or a vast distance I have no basis to understand, I like to make comparisons. My reasoning is that if I can’t understand something in absolute terms, maybe I can understand it in relative terms.

It’s also really fun to compare things that aren’t normally compared.

For example, there are more atoms in a single grain of sand than there are grains of sand on Earth. If you’re Cliff on Cheers, you will happily collect this tidbit of information for your eventual Jeopardy appearance, but what about for the rest of us?

It turns out that stretching your brain in this way is very useful. Here, we can understand that the world of the very tiny is every bit as wondrous and complex as the world of the very large. Consider how small and insignificant the size of a grain of sand seems to you when you brush it off of your bed sheets at the beach, and then remember that there’s a tiny world of atoms in there.

Think for a moment about all those atoms inside of one single grain of sand. Now think of all the sand on Earth, and all those other atoms on the planet. Think of all the planets and all the stars in the cosmos put together, and add all those atoms up. Even then, the number of possible chess games is greater than the number of atoms in the observable universe.

This one takes us outside of the realm of the planet and into the cosmos, where we can think about truly vast distances and compare them to other things. For instance, the stars in a galaxy are very, very far apart. While light takes 8 minutes to reach Earth, it takes four years to reach our nearest stellar neighbor, Proxima Centauri.

Even still, the distance between atoms in a diamond is proportionally far greater than the distance between stars in a galaxy. There’s that idea of the universe of the very small again.

In a great cosmic coincidence, the Sun is about 400 times larger than the Moon, diameter-wise. However, when you look at the sky, the two bodies appear almost the same size! That’s because the Sun is about 400 times further away than the Moon.

This brings things closer to the realm of human experience, so that’s where I’ll focus for the rest of today. Let’s go back inside our bodies for a moment, shrinking down to the size of a cell. You need a microscope to see a blood cell, and yet inside of that single cell, there’s about 2 meters of DNA.

As wild as that is, here’s an even crazier fact about the human circulatory system: all of the blood vessels in one person’s body, lined up end-to-end, would circle the earth two times. By contrast, all the roads we’ve ever built add up to about 64 million kilometers (almost 40 million miles). That takes you to the Moon and back a few hundred times, it only takes you about halfway to the Sun.

By contrast, the average ambulatory person walks the equivalent of five times around the Earth. Lao Tzu famously said that a journey of a thousand miles begins with a single step, but the average person walks around 125,000 miles.

There are many more of these sorts of useful comparisons to be made. The idea is to seek to understand something that seems insurmountable, by way of comparing it to something else. That way, at least we can get a relative sense of the thing.

I’ll leave you with one of my favorite things to consider, one that places humanity into its proper place in the cosmos: the amount of energy our Sun releases every single second is more than the total energy produced by humanity in its entire history. All that stuff we’ve ever dug up out of the ground, everything we’ve burned and everything we’ve ever done seems like an awful lot, and it is!

And yet, one mere second (out of billions of years) of the Sun’s energy is more than we’ve created so far.

The universe is only this much fun to think about once you have a comparison to make, so the thing is much more understandable to you. Have you ever made any of these sorts of observations or comparisons? What are some of your favorites?