If You Get My Continental Drift

Your Mattness:

Who decides what are continents? Why is Greenland not a continent? It is bigger than the island/continent of Australia and has more people than Antarctica. How can Europe and Asia be one continent? Where is the dividing line? Where does Central America fit in?

-- We Must Know, San Diego

If you've got the spare time, you guys can decide what a continent is. The field's wide open. Look up the word in the dictionary, ask geologists or geographers, and all you get are weasel words-- something about a continent being a big body of land, larger than an island, surrounded by water. But don't ask 'em how big an island is because they don't have a good answer for that either. In desperation, I imagine, a spokesman for the Association of America Geographers suggested that a continent is like love. You know it when you see it, but no one can really describe it adequately. "Continent" is a useful catch-all word in certain situations but has no clear scientific meaning.

The ancient Greeks, who first dreamed up the concept, recognized three continents: Europe, Asia, and Africa. Today we consider the Ural Mountains in Russia the dividing line between Europe and Asia (though some consider the whole area the Eurasian continent). But the Greeks separated Europe from Asia using cultural as much as geographic guidelines. And that's where most of our present confusion starts. For example, North, South, and Central America make up a single land mass but are generally considered two continents. That's a decision based on history and culture. And of course you can put Central America wherever you want, since there's no single definition of North or South America.

You can call Australia a continent if you like but many geographers say it's just a very big island. And if you can't take any more of these wishy-washy answers, I'll tell you definitively that Greenland is only about one third the size of Australia. You've been looking at too many Mercator-projection maps, which tend to exaggerate the size of things near the poles. Check it out on a globe.

Hot activity for geographers has been devising computer-useful definitions for relational concepts like "near," "far," "north," and "south." I was assured that once they had the compass points pinned down they'd get right on a definition for "continent" and give me a call. Don't wait up.