Let’s face it: kids are not smart. That’s fine; they’re not meant to be – they have a lot of growing and learning left to do, and they can’t be spending that time grappling with the finer nuances of special relativity when “apples fall down because gravity” will serve them just as well.
But it does mean that a lot of what we learn in elementary school often turns out to be… well, not exactly false – but not true, either. No, the Earth isn’t a sphere; no, sex is not a binary; and no, gasoline is not made from dinosaurs (we know; we’re sad about it too).
And you know what else? There aren’t seven continents, either.
Broke: seven continents
So, let’s start with the basics. We all know there are seven continents, right? That’s what we’re taught in elementary school; there’s even a song about it.
In alphabetical order, we’ve got: Africa; America, North; America, South; Antarctica; Asia; Australia; and the only non-A of the lot, Europe. But – hang on. Let’s take a closer look at that last one.
That line seems a bit arbitrary, doesn’t it?
Image credit: Pyty/Shutterstock.com
Is that… really a continent? Or is it just, you know… the westernmost bit of Asia?
“Europe is a stupid idea for a continent,” says Jonn Elledge, author of A History of the World in 47 Borders: The Stories Behind the Lines on Our Maps. “Its boundaries with Asia are mainly tiny inlets, inland seas, or not especially impressive mountain ranges.”
“It is an invention springing from three things,” Elledge tells IFLScience. “1) an understandable ancient Greek impulse to put themselves at the center of the world, without the knowledge to tell them that Europe and Asia actually connected up round the back of the Black Sea; 2) the rise of Islam, making a bunch of previously culturally similar territories seem strange and alien to each other; 3) European imperialism meaning that we got to set the global rulebook.”
Woke: between four and nine continents
So, strike Europe off the list – are there in fact six continents, not seven? Maybe – but as the New York Times points out, once you start with this reasoning, it can be difficult to stop. It was only comparatively recently that the Bering Strait was a perfectly usable land bridge connecting Asia to North America; some experts think their tectonic plates haven’t broken apart yet. Knowing that, can we really justify their being two separate continents?
Well, perhaps it would help if we found the definition of the term “continent”, right? Then we can just match up our various landmasses to it, and count how many we get. Here’s the problem, though: “Nothing, really, determines a continent, except historical convention,” Dan Montello, a geography professor at the University of California, Santa Barbara, told HowStuffWorks.
“Certain factors make a landmass more or less likely to be called a continent at various times in history, by various people,” he added, “but nothing can be said to determine continentality in a completely principled, nonarbitrary way.”
Now, we know that doesn’t sound right – surely, such a foundational concept must have some physical, formal definition, right? Maybe something to do with plate tectonics, or even traditional cultural ties? But the truth, Montello explained, is far messier: “Plate tectonics has nothing to do with it historically, and it certainly could not provide a principled basis for continents now,” he said; “nearly every continent includes parts of multiple plates, and continental boundaries are not, and have never been, defined by plate boundaries.”
Similarly, “neither ethnicity, race, culture, nor politics has ever defined continents,” he added, “except by conventional theories that were largely mythical.” Take Greenland, for example: politically European; geologically American. Or Hawai’i: not part of North America in any geographical sense, but undeniably part of that continent’s second-largest nation.
Okay, so let’s forget geography and politics. Ask a geologist for their definition of a continent, and you’ll probably be given a four-point checklist: to qualify, a bit of land has to have a high elevation relative to the ocean floor; a variety of rock formations which include igneous, metamorphic, and sedimentary rocks; a thick crust – noticeably thicker than the surrounding oceanic crust, at least; and clearly defined boundaries around a big enough area.
As you may have noticed, though, one of those criteria is not quite like the others. Who decides what is “big enough”? How “clear” is “clearly defined”?
“Anything big enough to change the map of the world is important,” Nick Mortimer, a geologist with the New Zealand government-owned GNS Science research institute, told the New York Times. “Labeling and identifying part of the Earth as a continent, even a small, thin and submerged one, is more informative than just leaving a map blank.”
Hence, for example, Zealandia – the almost-entirely submarine continent that contains New Zealand, and is increasingly considered Earth’s eighth continent. It meets at least three of the criteria above: its crust is between 10 and 30 kilometers (6.2 and 18.6 miles) thick – not as hefty as other continents’, but still an increase on the 6 or 7 kilometers (3.7 or 4.3 miles) of oceanic crust; it certainly contains a variety of rock formations; and despite being underwater, it is elevated above the ocean floor. In short, the Geological Society of America (GSA) concludes, “the identification of Zealandia as a geological continent, rather than a collection of continental islands, fragments, and slices, more correctly represents the geology of this part of Earth.”
On the other hand, Zealandia is small – and the tiny section of it that we can actually see is even smaller. At less than 5 million square kilometers (1.9 million square miles), does that count as a whole continent? Or just an oddly thick bit of crust?
And, if Zealandia counts, how about “Icelandia” – the even smaller continent potentially hidden under the seas around Iceland? “Until now Iceland has puzzled geologists,” Gillian Foulger, Emeritus Professor of Geophysics in the Department of Earth Sciences at Durham University, told the GSA back in 2021. “For example, the crust under Iceland is over 40 km [25 miles] thick – seven times thicker than normal oceanic crust. This simply could not be explained.”
“However, when we considered the possibility that this thick crust is continental, our data suddenly all made sense,” she explained. “This led us immediately to realize that the continental region was much bigger than Iceland itself – there is a hidden continent right there under the sea.”
So, are we now up to nine continents? Eight, if we discount Europe? Or are we going to lean all-in to the “large and distinct” criterion, and say there are only four – AfroEurasia, America, Antarctica, and Australia?
Honestly, you could – and people do – justify going in either direction. “Continents are made up,” Elledge tells IFLScience. “They don’t have any existence that isn’t socially constructed, they’re not all separate landmasses or tectonic plates or anything.”
Bespoke: two continents
Okay. Enough is enough, you might be thinking at this point: it’s time to draw a hard line. Anything that falls on this side is a continent; everything else is just an island.
Well, we can do that, but you might not like the results.
“There are basically only two major continents,” Valentin Rime, a geologist at the University of Fribourg, told the New York Times. “[There’s] Antarctica and everything else.”
You may scoff, but the argument is sound: “South America is connected to North America through Panama,” he pointed out; “North America is connected to Asia through the Bering Strait, and Asia is connected to Europe, Africa and Australia through the Urals, the Sinai and Indonesia, respectively.”
There’s a bit of wiggle room, and it’s not where you might expect: “Zealandia is separated from Australia by a 25-kilometer-wide [15.5-mile], 3,600-meter-deep [11,800-foot] ocean trough,” Mortimer said. “Based on Valentin’s logic, that would mean there are actually three continents.”
Overall, though, the question of “how many continents are there?” basically depends on when, why, and whom you ask. “No one can say as a matter of principled fact how many continents there are, because the decisions are largely based on convention, and convention that goes in and out of fashion over time, and is still debated today,” Montello told HowStuffWorks.
“There simply is no ‘czar’ or ‘CEO’ of continents or any other ultimate authority,” he said, “so it is pretentious for anyone to claim they have the authoritative answer.”
Source Link: There Aren't Seven Continents, There's Two. Or Four. Or Nine. Wait, What?
