It is widely believed in much of the world that Earth has seven continents: Asia, Africa, North America, South America, Antarctica, Europe, and Australia. However, this concept is not as definite as one might think for many reasons.
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To begin, there is no consensus among the scientific community regarding what exactly a continent is. One common definition, as provided by World Atlas, defines a continent as “one of the seven large land masses on the earth’s surface, surrounded, or mainly surrounded, by sea, and usually consisting of various countries.” Geologists, on the other hand, tend to identify continents based on the location of continental plates (1). Yet no one definition is able to provide a clear distinction between what qualifies as a continent and what does not in a way that removes all ambiguity.
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To provide some examples, many professionals believe that Europe and Asia, which are not separated from one another by a body of water, should be considered as one continent: Eurasia. Some even believe that Africa, which also lacks a complete separation by water, should be grouped into the continent. Others believe that North America and South America should be considered as one continent, known simply as America, based on the fact that the only body of water that separates them is the man-made Panama Canal. The argument against this relies on the cultural, political, and historical differences between these regions that, some believe, justify them being separate continents (2). Additionally, Australia is considered to be a continent, while Greenland, another large landmass that is surrounded by an ocean, is considered to be part of North America. Other smaller land masses which do not fit neatly into any one continent, such as Madagascar, Hawaii, and French Polynesia, exist as well and they are referred to as microcontinents (3).
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While geologists rely on a different definition that utilizes plate tectonic theory, their definition has its own set of difficulties. Many continental plates overlap, making the process of demarcating continents with this definition rather difficult. Additionally, many commonly accepted continents span multiple continental plates. For example, most of the continent of Asia is located on the Eurasian plate, while the Arabian peninsula is located on the Arabian plate, the Indian peninsula is located on the Indian plate, some islands of Indonesia are located on the Australian plate, and eastern Siberia and the northern islands of Japan are located on the North American plate (3). Clearly, there is no easy way to determine the exact number of continents we have on Earth and what those continents are, leaving room for interpretation by different individuals.
To further muddy the waters, there recently has been a push to classify Zealandia, a lesser-known landmass, as its own continent based on extensive research. For the past twenty years, a team of geologists at GNS Science, a New Zealand Crown Research institute, has been gathering data to prove that New Zealand is not merely a collection of islands, but rather the tip of a 4.9 square million kilometer and 94% submerged continent (4). Their research led to the publishing of a paper, titled “Zealandia: Earth’s Hidden Continent,” in February of 2017. The paper supported the classification of Zealandia as a continent on the basis that Zealandia’s continental crust is large and separate enough to be its own continent, as well as the fact that the landmass adheres to many other principles of what a continent is. Following this paper, much of the scientific community has accepted Zealandia as a continent (5). Another study by a 32 member team aboard the research vessel JOIDES Resolution also supports this conclusion. During their nine-week voyage in late 2017, the researchers learned more about the landmass, which is submerged nearly one kilometer under the sea, through ocean drilling. The sediment cores and fossils they collected have revealed more about Zealandia’s history, including that its climate, volcanism, geography, and wildlife have changed dramatically over time and that the landmass was likely submerged 80 million years ago when it split from Antarctica and Australia. (6)
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However, the discovery of Zealandia’s significant submerged portion and its classification as a continent has failed to carry over with as much success into the general population. Students around the world are most often taught a seven-continent or six-continent model, neither of which include the addition of Zealandia.
Yet, the scientific research done in the case of Zealandia is very important. For one, it serves as a reminder that although science has taught us a lot about the world around us, there is still much left to discover. Although most individuals accepted the fact that there were a set number of continents, whatever they believed that number to be, the discovery and classification of Zealandia as a new continent has proved the importance of not relying on assumptions and of always being open to new information. Additionally, scientists are optimistic that the newly discovered continent will be extremely valuable in learning about oceanographic history, plate tectonic theory, extreme climates, undersea life, wildlife development, and in a variety of other areas and they are excited to explore the landmass further.
(1) Nag, Oishimaya Sen. “Defining What Exactly Is A ‘Continent.’” WorldAtlas, WorldAtlas, 22 Feb. 2016, http://www.worldatlas.com/articles/definition-what-is-a-continent-science-vs-convenience.html.
(2) “The Continents Definition: What Is a Continent Exactly?” The 7 Continents of the World, http://www.whatarethe7continents.com/the-continents-definition-what-is-a-continent/.
(3) National Geographic Society. “Continent.” National Geographic Society, 9 Oct. 2012, http://www.nationalgeographic.org/encyclopedia/continent/.
(4) Parnell, Brid-Aine. “New Zealand Is Not Just A Small Bunch Of Islands – It’s The Lost Continent Of Zealandia.” Forbes, Forbes Magazine, 17 Feb. 2017, http://www.forbes.com/sites/bridaineparnell/2017/02/17/the-lost-continent-of-zealandia/#6fd9628854e7.
(5) Zareva, Teodora. “Earth’s Hidden Continent Zealandia Finally Recognized.” Big Think, Big Think, 4 Oct. 2017, bigthink.com/design-for-good/earths-hidden-continent-zealandia-finally-recognized.
(6) “National Science Foundation – Where Discoveries Begin.” NSF – National Science Foundation, http://www.nsf.gov/news/news_summ.jsp?cntn_id=243192.