Why are the laws and theories of science so powerful? Science writers love to answer this question. Go read a prologue or introductory chapter of a science textbook of any grade level. You will learn that the laws and theories that the book presents have met some strict criteria. Scientific ideas must be testable and they must pass those tests, over and over again. If new evidence arises that fails to support an existing idea, then scientists are charged with revising or replacing their old paradigms as necessary. No precept of science is grated immunity.
However, this lofty claim has one big catch: Revising science takes time. Sometimes a few years, sometimes much longer.
Scientists, as part of their training, tend to be skeptical of new conclusions and unexpected outcomes. That’s helpful, because a lot of unexpected outcomes prove to be pure bunk. Only after thorough vetting, both formal and informal, will a radically new idea gain widespread acceptance. Admission into science textbooks is, arguably, the last step of the process.
For an historical example of this slow process, let’s consider the work of German meteorologist Alfred Wegener (1880–1930.) Just now I paged through an Earth science textbook for middle school. Along with a few astronomers, Wegener is one of the few scientists whose names and contributions are presented in the main narrative. That’s an astounding turn of events for a man who, in his lifetime, was widely ridiculed or ignored.
In 1912, Wegener offered the heretical proposal that the continents were once joined together into a huge land mass, which he called Pangaea. Over time the continents slowly separated, eventually reaching the positions we see now. Wegener cited much evidence for this model, including the matching coastlines of continents—notably South America and Africa—as well as matching fossils and rock layers along those coastlines. But the big hole in Wegener’s argument was propulsion. The continents appeared to lack the outboard motors necessary for putt-putting like tugboats across the ocean.
The world’s professional geologists needed several decades to stop laughing at Wegener and begin to take his ideas seriously. Surprising evidence was being gathered from the ocean floor, including matching bands of oceanic crust that surrounded an unexpected chain of volcanoes. Eventually, in the mid 1960s, the scientific community came to accept the theory of plate tectonics, which describes both continents and oceans as moving pieces. The motor for their movement is convection currents within Earth’s mantle. Today, the global positioning system (GPS) shows that Greenland, where Alfred Wegener is buried, is moving toward North America at a rate of about 2 centimeters per year.
We can cite some more recent examples of slow, gradual changes in science dogma. One nominee is Linnaean taxonomy. This is the time-honored method of classifying organisms into hierarchical groups—domain, kingdom, phylum, class, and so on down to genus and species. Yet among the experts, taxonomy has been overhauled by cladistics, a new system based entirely on evolutionary relationships. If cladistics isn’t discussed in your current biology textbook, wait for the next edition—or perhaps the edition after that. The development of cladistics dates back to 1957, if not earlier. There doesn’t seem to be much urgency.
Which brings me to a question: Has a bedrock lesson in K-12 science ever changed extremely quickly, in a manner of days or weeks instead of years and decades? The answer is yes. I can think of one example, and we’re now approaching its 20-year anniversary. It’s the reclassification of Pluto—formerly the ninth planet, now recognized as a dwarf planet.
Let’s start at the beginning.
In 1930, astronomer Clyde Tombaugh discovered the distant object that was soon deemed Pluto, the ninth planet, named after a god of the underworld. Ever since, school children everywhere learned about Pluto and its many eccentricities. Pluto is small and rocky, making it more like an inner planet than an outer one. Pluto’s orbit is both tilted and stretched, occasionally bringing it inside the orbit of Neptune. Pluto has a moon, named Charon, that is nearly Pluto’s twin. And as my eight-year old son would insist I mention, Pluto also leant its name to a popular cartoon dog.
However, by the 2000s, Pluto’s status was becoming a little shaky. Turns out that the ninth planet wasn’t such an oddball after all. Astronomers had discovered a number of rocky objects in the distant reaches of the solar system, and some of the objects had Pluto-like size and mass. Some basic questions were proving difficult to answer. Should all these new objects be called planets? If so, then how many planets are there? Good grief, what is a planet anyway?
Resolution arrived on August 24, 2006, when the International Astronomical Union (IAU) voted to “decommission” Pluto as a planet—as one commentator put it. Instead, the IAU classified Pluto and similar bodies into a new category: the dwarf planets. If August 24 is your birthday, feel free to accept kinship with the dwarf planets, of which there may be hundreds.
As I’m guessing the IAU was unaware, the timing of their announcement was outstanding for disrupting the lives of editors of science textbooks. I know this because I was one of those editors, on staff at one of the major publishers. My colleagues and I had just completed a new edition of our program for the state of California, and their textbook commission was asking for Pluto revisions. Thus I was charged with hunting down and updating all references to Pluto, incorporating a definition of the dwarf planets, and revising phrases such as “the nine planets” (now only eight) and “the five outer planets” (now only four.)
Somehow, we cranked out our revised, Pluto-accommodated California textbooks and ancillaries in about a month, as necessary to meet the California deadline. Other publishers did exactly the same.
So what made Pluto’s reclassification so special? Why did it receive instant accommodation in textbook-world, while other changes in science are kept waiting in the wings? I would like to propose a simple explanation:
Pluto makes an outstanding story.
Scientific proclamations are often gobbledy-gook to the lay person, but everyone could understand Pluto. Back in 2006, the media seized on the story and made it front-page news. The general public, not just the science-minded, were paying attention.
Like all great stories, the reclassification of Pluto had an empathetic lead character. That character was Pluto itself. A tiny, cold, and distant hunk of rock was plucking heartstrings. An editorial cartoon showed the bigger planets ganging up on Pluto. On my Facebook page, more than one friend posted the phrase “Poor Pluto!” Someone I know claimed the website Plutoforplanet.org.
Despite all the grumbling, I never heard anyone question the IAU’s right to define planets for the rest of us. When the story finally died down and the dust settled, the reclassification of Pluto seemed permanent. Today, textbooks and other reference sources identify Pluto as a dwarf planet without much controversy or complaint.
What lesson can we learn by comparing Alfred Wegener—who needed 60 years to break into the science curriculum—with Pluto as a dwarf planet—which did so in about 60 seconds? I think the comparison shows that science is, at its heart, a human endeavor. Yes, science is based on evidence and logical reasoning, but it’s also subject to human biases and foibles, to human stubbornness and passions, to both logic and emotion, making science, at least in some ways, like any other field of study or way of experiencing the world. None of these fields should be ceded to computer algorithms or other automatic protocols.
Science and science education belong to humanity. I wouldn’t want it any other way.
