Here is the next entry in my series on science questions.
It’s icy cold, it’s dark and distant, it’s PLUTO, a planet (sort of) with powers far beyond those of any gas giant or terrestrial pipsqueak, including Earth. For Pluto is not merely a planet or dwarf planet, but a body that is INTERESTING, and dare we say, CONTROVERSIAL! Neptune may be colored a pleasant blue, and Jupiter may have its big red spot, but only Pluto has inspired special legislation in Arizona, where it was discovered, and Illinois, where its discoverer was born.[1]
Question 8: What’s so freakin’ special about Pluto?
A generation ago, this question had an easy answer. Pluto was the ninth planet, both the most distant and the smallest, and something of an oddball. Pluto was rocky, like the inner planets, but positioned just beyond the four gas giants of the outer planets. Pluto’s orbit was slightly tilted compared to the rest of the solar system, and it was unusually stretched. The orbital path was so stretched that it intersected the path of Neptune, although because of lucky timing the two planets are never in danger of colliding.
Anecdotally, Pluto was the most popular choice of planet for second-grade science reports. It also is the only celestial body that has leant its name to a Disney character. We can all identify with the plight of Pluto, assuming Pluto has plight to begin with.
Then in 2006, everything changed.
The problem was not Pluto’s fault (how could it be?) The problem was that astronomers had discovered a small carload of Pluto-like objects in the deep recesses of the solar system. Turns out Pluto isn’t such an oddball after all. One of the new objects, named Eris, proved to be more massive than Pluto, albeit not quite as large.[2] Shouldn’t Eris be classified as a planet? If not, then just what was it? Certain people are kept up at night by contemplating questions like these.
At a meeting of the International Astronomical Union (IAU), the wizened elders debated the surprisingly vital question of how to classify Pluto and its ilk. If these objects were all planets, then the contingent of planets would swell to as high as 12, with future discoveries threatening to raise the number ever upward. Instead, the IAU decided to kick Pluto out of the planet club. Pluto became a member of a new class of solar system objects, called the dwarf planets. Other dwarf planets included Eris, Ceres, Haumea, and Makemake, all names that children might now be memorizing in a classroom near you.
The IAU announced their decision on August 24, 2006. If this date is your birthday, then you share it with the dwarf planets.[3]
Yet while Pluto is no longer special as a planet, its story is now special—even unique—in the annals of science, or at least science education. The uniqueness is not obvious, and no one but me and a few others may really care. But here are the three reasons that Pluto’s reclassification is like few other changes in science history:
1. Pluto was front-page news on that summer day of 2006. If you were paying even modest attention to the world at large, you knew about the reclassification.
2. The reclassification was easy to understand. You could summarize it in a sentence.
3. Despite a little grumbling here and there, most everyone accepted the reclassification fairly quickly. Certainly in my world—science educational publishing—the IAU announcement led to changed textbooks almost immediately after we learned about it.[4]
As scientists and science teachers like to claim, science is a strong, vital pursuit because it accepts new ideas or theories in light of new evidence. What scientists tend not to point out is that the process of change happens slowly, and often erratically, within the science community. Especially in science textbooks, which are written to meet academic standards and the expectations of teachers, new ideas or developments in science are slow to take hold. And for good reason, because many new ideas prove to be rubbish.
The reclassification of Pluto is unique because it occurred so swiftly and with rapid acceptance. One day Pluto was a planet, the next day it wasn’t.
For a more typical example of changing science knowledge, consider the classification of a biomolecule called ribonucleic acid, or RNA for short.
Ask a biology teacher or well-versed student to discuss RNA, and you will learn about three variants: messenger RNA, ribosomal RNA, and transfer RNA. All three are produced by RNA’s more famous cousin, DNA.
To the surprise of many science folk (including myself, when I learned of it) RNA has more variants than the familiar trinity. A class called micro RNA was discovered in the 1990s. Its function includes regulating the activity of other RNA molecules. In 2024, researchers who studied micro RNA were awarded the Nobel Prize.
Just now I opened up my favorite high school biology textbook.[5] In the appropriate chapter I read that RNA has three main forms (emphasis added.) Then the text lists and describes the familiar three examples. The presentation is accurate, but micro RNA is not mentioned. And it’s been known for over 30 years now.
The problem—if you want to call it a problem—is that discoveries in science don’t generally get much publicity and attention, at least outside certain academic circles. The discovery of micro RNA is typical because it was barely publicized and, at least for non-scientists, it is not easy to understand. Even the awarding of a Nobel Prize—which is how I learned about micro RNA—is usually part of the general clutter and clamor to which we are all subjected.
But while change to science dogma may come slowly, it does come eventually. I predict that micro RNA will soon make its way into high school biology curriculum, especially if it is spurred on by a few more important discoveries, or perhaps a new biotechnology that makes the headlines, Let’s give micro DNA another 10 years, maybe 20 at the longest. And then we can find something else to fuss over.
Question 9: Whether Pluto is a planet or not, what difference does it make?
Versions of this question were asked, rhetorically, by people who opposed the IAU’s reclassification. The logic was that calling Pluto a dwarf planet would make no difference to Pluto or to anyone interested in it, so why bother upsetting the apple cart?
I can tell you that the IAU announcement about Pluto caused a significant, albeit short-term effect on the lives of at least a dozen people I could name, and certainly many others. I am one of these people. In 2006, we all worked in the business of publishing science textbooks.
The reason was timing. The date of the announcement—August 24, 2006—was incredibly ideal for screwing up the California science adoption.
Had the announcement been released two months earlier, we editors could have easily revised the books to incorporate the new dwarf planets and the repercussions. (The solar system now had 8 planets instead of 9, Neptune was now the outermost planet, Mercury was the smallest planet, and so on.) Had the announcement arrived two months later, then too bad[6], the books would have been adopted and finalized. Californians would have had to live with Pluto as planet for a while longer. Maybe we would have acknowledged the change on an Internet page.
Instead, the announcement coincided with the California cognoscenti officially reviewing our submissions for accuracy, including the chapters on the solar system. I like to imagine one reviewer actually reading the section on Pluto when they heard the news.
So, California officials were well within their rights to ask for the books to be revised to accommodate Pluto as a dwarf planet. And the publishers had no choice but to agree, which meant stomaching some significant expenses and employee-hours of effort.
I was in charge of the editorial revisions for the publishing company at which I worked at the time. For this reason, I got a free trip to Sacramento out of the deal. My boss and I attended a meeting of the adoption committee and explained the changes we made. We also hobnobbed with friends who worked at other publishing companies and who were doing the same thing. Later, we had dinner at a nice restaurant.[7]
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This brings us to the close of another edition of….Confounding Questions in Science! If you think today’s questions weren’t especially confounding, please refer to footnote number 6.
[1] The lucky astronomer was Clyde Tombaugh, who compared photographs of the night sky to find a new wanderer among the stars. This happened in 1930,
[2] Eris was named after the Greek god for strife and discord. Nice choice!
[3] I’m always open to party invitations, especially if you’re serving cake and ice cream. I might even bring a gift.
[4] Immediately in extremis. See the next question and its answer, which deals with how the reclassification affected my life.
[5] I spent several months contributing to this particular textbook, and nearly all of my efforts wound up on the cutting room floor. That I still consider it my favorite biology textbook might tell you something about me, although I have no idea what.
[6] Tant pis pour vous, as I learned in high school French.
[7] I am less enamored of business travel than I used to be, in part because stuffing myself into an airplane feels less and less like a wonderful thing to do. But I grew up in an era when commercial airlines were gateways to adventure and sophistication, or so I could at least pretend. I lived in Minnesota, where life certainly was pleasant, albeit a tad on the mundane. I was always up for a trip into the skies.
I checked my records—and yes, I record all my airplane and train trips in an ongoing journal —and they show that the Sacramento trip took place in November, 2006, about three months after the IAU announcement. We publishers must have needed that time to revise the books before reconvening with the adoption committee. My records show that I stopped in Colorado on the way home for a day of skiing at Copper Mountain. Woo-hoo, good for me! The journal entries also suggest that I was not as consumed by the Pluto stuff as I was with the ongoing development of my son, age 19 months at the time. Three more cheers for me, for recording memories worth remembering.
Over the years, business travel has brought me to many interesting places on many bizarre itineraries, the bizarreness due mostly to my own machinations. By far the most exotic flight segment that a company paid me to take was on Etihad Airways, nonstop from Abu Dhabi to Geneva (that’s AUH to GVA, if you speak luggage tag.) The aircraft was a double-decker Airbus A380. I imagined my fellow passengers to be oil ministers, international bankers, British secret agents, downhill ski racers (the month was January), and perhaps a famous actress like Julie Andrews, to pick a name more or less at random. Perhaps Dame Julie might have wanted a Swiss stopover en route home from a foray to the middle east, which was in fact my reason for this particular itinerary. In reality, AUH to GVA was like any other flight I’d taken, albeit significantly longer and staffed by flight attendants wearing hijabs. The passengers seemed like passengers everywhere. I didn’t even earn as many frequent flier miles as I had expected.
You may be wondering what business I had in Abu Dhabi, but the answer is even less interesting than the associated airplane flights, so I’ll skip the discussion for now.
For a few years, I flew so often that I earned platinum elite status on Northwest Airlines. Many of my travel machinations (see the longer of the two paragraphs before this one) involved flying on Northwest or its partners to bolster and take advantage of this status. Almost always I was upgraded to first class, where soon after settling into my comfy and roomy seat, a flight attendant would approach and ask, “Can I get you something to drink?” Unless the time was crack of dawn, I would reply, “You know, I think you can!” And I’d ask for a Bailey’s on the rocks, a beverage of which I never partook otherwise. It went down easy on those flights from Memphis to New Orleans, or Detroit to Miami.
Those were good days. My elite status on Northwest is long gone, as is the airline itself. I now fly in steerage class with everyone else. But don’t confuse my documentation with complaining.
