There areseven continentson Earth . That ’s what we learn in elementary school , along with " two plus two equals four " and " the creation is circular . "
Pretty basic stuff , right ? Only that last one is n’t quite as cut and dried as our first - grade teachers led us to believe .
In the United States , scholarly person find out that there are seven continent :
locomote by that standard , continents make up the vast majority of land surface area on the planet , or about 57 million square air mile ( 148 million substantial kilometers ) .
But that ’s scarcely the last word on the matter . For illustration , in Europe , students commonly learn that there are actuallyonly six continent : Africa , America , Antarctica , Asia , Australia / Oceania , and Europe . There ’s even afive - continent model , which lists Africa , Europe , Asia , America and Oceania / Australia . ( That ’s why there are five rings on the Olympic flag . ) And some expert retrieve four is the way to go , using as their criteria landmassesnaturallyseparated by water system , rather than manmade canals ( AfroEurasia , America , Antarctica and Australia ) .
Heck , as recently as the 1800s , some masses say there werejust two continents , the Old — including Europe , Africa and Asia — and the New , which encompassed North and South America .
It does n’t take much resource to see why this is more complicated than it seems . Even as a child , you may have wondered how anyone would regard Asia and Europe as different continent when they are weld together in enormous expanse of kingdom .
rent ’s try out to simplify .
What Makes a Continent a Continent?
Traditionally , we ’ve learned the Christian Bible continent set an enormous land mass with distinctly defined edge disunite by oceans .
According to a 2017 paper print in the Geological Society of America ’s journal , GSA Today , " The ' Glossary of Geology ' defines a continent as ' one of the Earth ’s major land mass , admit both dry land and continental shelves . ' It is more often than not agreed that continents have all the following attribute : ( 1 ) gamey superlative comparative to regions floored by oceanic crust ; ( 2 ) a broad range of silicious igneous , metamorphous and sedimentary rocks ; ( 3 ) thicker crust and lower seismal velocity social organisation than pelagic crustal region ; and ( 4 ) well - determine limits around a orotund enough area to be consider a continent rather than a microcontinent or continental shard … To our cognition , the last item — how ' major ' a piece of music of continental crust has to be to be called a continent — is almost never discussed . "
" Nothing , really , ascertain a continent , except historic formula , " says Dan Montello , a geography prof at the University of California , Santa Barbara , via email . " A bit of an exaggeration but mostly valid . Certain factors make a landmass more or less probable to be called a continent at various sentence in account , by various people , but nothing can be say to limit continentality in a completely principled , unarbitrary path . "
Take for example , the vast state of Russia , 6.6 million square miles ( 17 million square km ) . Why is it part of Europe rather than Asia ? " The Ural Mountains are take to separate Asia and Europe but only because Russians wanted their great metropolis of Moscow to be European , so the Urals were a convenient marking for that arbitrary decisiveness , " read Montello .
" Continents are ( mostly ) spatially neighboring collections of landmasses large than countries but pocket-size than cerebral hemisphere ; of course , continent do not needs match entirely within single Earth hemispheres ( and , thus , can not be specify by ranges of parallel or longitude ) . "
How about home plate tectonics ? If sealed landmasses are constrained to one of those monumental shifting hulks , we can safely call it a continent ? Montello says no .
" Plate plate tectonic theory has nothing to do with it historically , and it sure as shooting could not provide a principled ground for continents now ; closely every continent includes parts of multiple plate , and continental edge are not , and have never been , set by plate boundaries . "
The same goes for climate . After all , Continent contain multiple mood , as attest by Alaska ’s Arctic tingle compared to Florida ’s humid heat , and they ’re both part of North America . deal orbit and continental shelf are n’t helpful , either , he says . Coastline is useless .
How about cultural link or politics ?
" Neither ethnicity , race , cultivation , nor politics has ever delineate Continent , except by conventional theories that were for the most part mythical , such as previous and fraudulent melodic theme about correspondences between races and continents , " he suppose . " Politically , Hawaii is part of the U.S. but is in Oceania rather than North America ; Greenland [ the world ’s declamatory island ] is controlled by Denmark ( for now ) but is considered part of the North American continent . "
Really , it may boil down to whom – and when – you take .
" No one can say as a matter of principled fact how manycontinentsthere are , because the decisions are largely based on convention , and convention that locomote in and out of manner over time , and is still debated today , " says Montello .
He concedes that these twenty-four hour period , many geographers would opt for a listing of seven Continent : Africa , Antarctica , Asia , Europe , North America , Oceania and South America . But he ’s also certain that some of them would combine Asia and Europe into one contient call Eurasia , identify Oceania in other way , or immix North and South America into the Americas .
" There just is no ' tzar ' or ' chief executive officer ' of continents or any other ultimate potency , so it is pretentious for anyone to claim they have the authoritative answer , " says Montello .
But do n’t worry , if you ca n’t treat that sort of definition , it ’s all deepen . Thecontinents are driftingat a rate of about an inch ( 2.5 centimeters ) per class .
