Considering the Universe as a Whole: We’re About Average Size

Don’t listen to those astronomers.

Some people have an inferiority complex about being smaller than average. Most people don’t like being just average, but being less than average is even worse. Astronomers like to take advantage of these people by pointing out that the universe is really, really big—much bigger than these below-average-sized persons. This is the astronomers’ story: Everybody, even the biggest guy, is shorter than, let’s say, a mountain. All the mountains on Earth are smaller than some of the mountains on Mars. Mars, itself, is very big, but not nearly as big as Jupiter and Saturn; and Jupiter and Saturn wouldn’t make a good-sized pimple if they sat on the surface of the sun.

The solar system revolves around the sun, according to modern theorists; but some of the planets are so far away, the sun—big as it is—would look like a pin, just one more star, to anybody standing on a mountain on Neptune or Pluto. That’s the solar system. Even bigger is the galaxy. The solar system is just one average-sized star about three-quarters of the way up one arm of the galaxy, sort of out by the edge as a matter of fact. The galaxy is really very big, even by the standards of other galaxies. If you set out in a rocket ship to go to the other end of the galaxy, it would take you forever. even if you were going very fast. One reason is that the other end of the galaxy is moving away all the while you’re sneaking up on it. There are billions of stars in our galaxy, many of them bigger than our sun, which is just average.

Even though there are billions of stars in our galaxy, maybe even more, there are more galaxies in the universe than there are stars in any one of them. That’s in the part of the universe we can see through telescopes. And who knows how far the universe goes beyond that, or how big it gets. Smaller than the universe, but much bigger than a big galaxy, are clusters of galaxies. These are called galaxy clusters, and they can include hundreds or thousands of galaxies, which can stretch over a considerable distance, as you might imagine. You could reasonably say that a big galaxy cluster is the biggest thing in the universe. When the astronomers smirk and tell you that you are really a very small part of the universe, they may be comparing you to a galaxy cluster.

But you are not so small (even if you are short) if you compare yourself to small things. For instance, you are much, much bigger than a bacterium, which is so small you need to look through a microscope to find it; and by the time you do find it, it has probably split in half and turned into two even smaller bacteria. Bacteria are the dominant (most numerous) organisms on Earth, even if they don’t know what they’re doing. But they are made of smaller pieces of things, like elements and other compounds that were formed in stars that blew up a long time ago and, probably, very far away. That doesn’t matter. These elements can be placed in columns on something called the periodic table, which I didn’t understand for the first time when I was in high school.

Elements are made up of neutrons and protons and electrons. The neutrons are very small, but even smaller are the protons and electrons (because neutrons are like a combination of protons and electrons.) Electrons are really tiny compared to the protons and neutrons. They are so small you can’t see them. (Electron microscopes use electrons but are not used to actually see the electrons.) Neutrons and protons and electrons make up atoms, which used to be what everyone thought were the smallest things; but they were wrong.

I could tell you just how small protons are, (not exactly since they are arguing about that right now) but I would have to look it up. They are millions and billions and thousands of billions of times smaller than bacteria, for example. And I’m sure they are even smaller than that. But they are not the smallest things! Inside the nucleus of the atom, where the neutrons and protons float around, there are still tinier things. (They float around inside the proton and neutron.) They are called quarks. Quarks come in different flavors, which is nice. Neutrinos may be even smaller, and yet there may be more neutrinos than anything else. Which reminds me, somehow, of the bacteria. Neutrinos are almost unimaginably small. In fact, I think they are unimaginably small. And just when you get used to these extremely teeny things being the smallest things, it may turn out that they are made of even smaller things called superstrings. (Not cosmic strings, which, if they exist, are even bigger than galaxy clusters.)

So, it turns out you are much, much bigger than the smallest things in the universe. In fact, by my calculations you are probably average-sized for the universe, about half-way between superstrings and cosmic strings.

Of course, you may be average-sized for the universe, but you can still be shorter than the other people you know. (c) Fredric Neuman