Bad Astronomy. Misconceptions and Misuses Revealed, from Astrology to the Moon Landing 'Hoax'

of the spring season. On or about March 21, schoolchildren, newspeople, and ordinary citizens take a chicken egg and try to stand it on end.

A nonscientific survey — conducted by me, by asking audience members when I give public talks and people I meet at parties or standing in line at grocery stores — shows that about one-half the population has either heard of this practice or tried it themselves. That’s roughly 130 million people in America alone, so it’s certainly worth investigating.

If you’ve watched this ritual, or have tried it yourself, you know that it takes incredible patience, care, and stamina. It also takes luck, a flat surface, and a sprinkling of bad astronomy.

At first glance you might not expect astronomy to play any great role here. However, like the cultural rites of ancient peoples, it’s the timing that’s important. This ritual is performed on the date of the spring equinox, which is the time when the Sun crosses from the southern to the northern hemisphere of the sky. The spring equinox is called the vernal equinox by astronomers; the root of the word “vernal” means “green,” which has obvious links to springtime. To my mind, the idea of balancing an egg is as strange a way to celebrate the spring equinox as is dancing at the foot of Stonehenge dressed as Druids.

So what are the details of egg standing, exactly? It goes something like this: According to the legend, it’s only possible to stand an egg on end and have it balance perfectly on the exact date of the spring equinox. Some people even claim that it must be done on the exact time of the equinox. If you try it any other time, even minutes before or after, you’ll fail.

That’s all there is to it. Seems simple, right? Every year at the magical date, newscasters — usually TV weatherpeople, since the date has climatological ramifications — talk on the air about balancing eggs. A lot of schoolrooms, in an effort to perform a scientific experiment, also try to get the little ova upright. Sometimes the newscasters will go to the classroom to show the tykes trying, and after a while, voila! Someone gets an egg to stand! The cameraman is rushed over and the beaming future scientist gets his or her face on TV that night, film at eleven.

Unfortunately, if the teacher doesn’t go any further, the child’s future as a scientist may be in some doubt. This hasn’t really proven the legend one way or another. Let’s take a closer look at it.

We need to start by asking what should be an obvious question: why would the vernal equinox be the only time you can do this? I have asked that of people who believe the legend to be true, and they make vague claims about gravity aligning just right on that special day. The Earth, the egg, and the Sun all line up just right to let the egg balance. But this can’t be right: there is always some point on the surface of the Earth exactly between the center of the Earth and the Sun. It has nothing to do with any special time. And shouldn’t the Moon have some effect too? The Moon’s gravitational force on the Earth is pretty large, so its gravity is pretty influential. Yet the Moon plays no part at all in the legend. Obviously, the vernal equinox is not the root of the issue.

Luckily, we don’t have to rely totally on theory. The legend of vernal egg-balancing makes a practical prediction that can be tested. Specifically, the prediction is: If an egg will stand only on the vernal equinox, then it will not stand at any other time. Once you think of it that way, the experimental verification is obvious: try to stand an egg on end some other time. The vernal equinox is usually on March 21 or thereabouts every year. To test the theory, we need to try to upend an egg on some other day, a week, month, or even farther from the time of the equinox. The problem is, most people don’t follow through with the experiment to its logical conclusion. They only try it on the equinox, and never on any other day.

However, I’ve tested it myself. The picture shows not just one but seven eggs standing on end in my kitchen. Of course, you’re skeptical — as you should be! Skepticism is an important scientific tool. But why take my word for it? Chances are it’s not March 21 as you read this. Go find some eggs and give it a try. I’ll wait.

Finished? So, could you do it? Maybe not. It’s not easy, after all. You need patience, a steady hand, and a fairly strong desire to balance an egg. After I got those eggs balanced, I had trouble balancing any more. My wife happened to come downstairs at that moment and asked me what the heck I was doing, and she quickly decided that it looked like fun. Actually, I think it was her competitive nature that drove her; she wanted to stand up more eggs than I did. She did. Actually, she had a hard time at first. I told her that I had heard it’s easier to stand an egg if you shake it a little first to help the yolk settle. She did, but pressed too hard on the shell. While she was shaking it her thumb broke through the shell, and she got glop all over the wall of our kitchen! I imagine we have the only house in the country where something like this could happen.

Standing eggs on end has nothing to do with the time of year, and everything to do with a steady hand, a bumpy egg, and lots of patience. These eggs were photographed in autumn, months after the vernal equinox. (But don’t take my word for it; try it yourself.)

Eventually, she was successful. She was the one who got the rest of the eggs to stand; we got eight total from that one carton. Clearly, her hands are steadier than mine. Once, when scheduled to give a public talk about Bad Astronomy at the Berkshire Museum of Natural Science in Pittsfield, Massachusetts, I arrived late due to an ice storm. I had to change my clothes quickly and literally run to the auditorium. When I arrived, I was out of breath and my hands were shaking a little from the stress and excitement. I usually start off the lecture by balancing an egg, but because I was shaking a little I had a very hard time of it! I struggled with the eggs all during the time the lecture series curator was introducing me, and by some sort of miracle I got it balanced just as he finished announcing my name. To this day, it’s the loudest and most pleasing ovation I have ever received.

The lesson here is that if you are patient and careful, you can usually get one or two eggs from a carton to stand. Of course, you can also cheat. If you sprinkle salt on the table first, it will support the egg. Then you gently blow on the remaining salt so that it gets swept away. The salt holding up the egg is almost invisible, and will never be seen from a distance. I, however, would never do something like this. Honest! Actually, over the years I have become pretty good at balancing eggs with no tricks. Practice makes perfect.

Still, this doesn’t answer the question of how an egg can balance at all. It’s such an odd shape, and oddly balanced. You’d really just expect it to fall over every time. So just why does an egg stand? I’ll admit to some ignorance of the structure of eggs, so to find out more about it I decided to find an expert.

I found a good one right away. Dr. David Swayne is a poultry veterinarian for the United States Department of Agriculture in Athens, Georgia. When pressed, he admits to knowing quite a bit about chicken eggs. I bombarded him with questions, trying to get to the bottom, so to speak, of the anatomy of an egg. I was hoping that somewhere in the structure of an egg itself was the key to balancing them (although I forgot to ask him which came first, it or the chicken).

The characteristic shape of an egg, he explained to me, is due to pressure from the chicken’s reproductive system as the egg is pushed through the reproductive organs. The yolk is made in the ovary, and the albumen is added as the yolk is forced through a funnel-shaped organ called an infindibulum. The white-yellow combination is only semi-gooey at this point, and it is covered with a membrane. The infindibulum forces the egg through using peristalsis, a rhythmic squeezing and relaxing of the infindibulum. The back part of the egg getting pushed gets tapered from being squeezed, and the end facing forward gets flattened a bit. That’s why an egg is asymmetric! Eventually, the egg reaches the shell gland, where it sits for roughly 20 hours and has calcium carbonate deposited all around it. That’s what forms the shell. The calcium comes out in little lumps called concretions, which is why eggs sometimes have little bumps on the bottom. Once the shell is formed, the egg goes on its way out the chicken. (At this point I’ll stop the narrative and you can use your imagination for the last part of the egg’s journey. After hearing Dr. Swayne discuss it I couldn’t eat an omelet for weeks.)

At this point I had two theories about egg balancing. One was that if you let the egg warm up, the albumen will thin a bit and the yolk will settle. Since the yolk moves down, the center of gravity of the egg lowers, making it easier to stand. Dr. Swayne put that to rest pretty quickly. “The viscosity of the albumen doesn’t depend on temperature,” he told me. “It’s designed to keep the yolk pretty much in the middle of the egg.” That makes sense; the yolk is the embryo’s food and shouldn’t get jostled too much. The albumen keeps it from bumping up against the inside wall of the shell, where it might get damaged. A thinned albumen can’t do its job, so it has to stay thick. Warming the eggs won’t help much in standing them on end.