We have finished our exploration of seven continents.
Everyone probably learned about these seven continents in elementary school, and they are pretty well established. The running community even had a marathon challenge where elites run seven marathons in seven days on seven continents. Amazing.
I first heard that there might be an eighth continent when the running community changed this challenge. Today it is eight marathons in eight days on eight continents. (The website page was updated, but the website URL didn’t change.) Why did runners think there was another continent?
The eighth contingent, called Zealandia, could be easy to miss since it is 93% underwater. Only New Zealand and New Caledonia are above sea level. However, the submerged section is elevated above the rest of the ocean floor. If the ocean was drained, it would be quite obvious that this landmass is a continent.
The evidence of an eighth continent has been studied since about 2007. Continents are usually made up of lighter (in weight) continental crust, while ocean seafloor is heavier. The rocks that make up the submerged plateau of Zealandia are lighter.
It might take a while before an eighth continent makes it into all the textbooks, but I think it is a great lesson about what a continent is and how we still have a lot to learn about this planet that we live on. For now, I’m going to go for a run.