Moment of Science: Islands

“The larger the island of knowledge, the longer the shoreline of wonder.” -Ralph W. Sockman
Dan Smith is getting a taste of the island life in your Moment of Science, exploring how keys, cays and archipelagos came to be. 🏝️
Published: Nov. 22, 2022 at 12:12 PM EST
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They say that no man is an island... even though a lot of islands are named after people. This week, we’re exploring how islands from Canada to the Caribbean came to be.

*There are two main types of islands: continental, and oceanic. The continental ones often form through a previous land link to the main continent being eroded or washed away, whether by retreating glaciers or huge waves. Great Britain is a great example, sitting on Europe’s continental shelf, but cut off from the mainland thanks to a massive tsunami over 60 feet tall, some 8000 years ago. Some people think of Australia as an island... but because it IS a continent, it doesn’t count. In that case, the honor of largest island goes to Greenland: over 800,000 square miles, more than double the size of New Guinea in the #2 spot. Baffin Island in Canada looks WAY bigger on most maps... but that’s the result of trying to make a sphere flat for mapping purposes, as northern areas will appear much larger. Northern Canada also has one of the weirder features, with an island in a lake in an island in a lake on Victoria Island, the world’s eighth-largest.

*Oceanic islands are something we’ve explored before. Earth’s crust gets drawn under another piece, subducting and melting into the planet’s magma. The resulting pressure release creates volcanoes, sometimes staying below the ocean surface, but oftentimes breaching the waters and layering lava over the years until it forms a new land mass. Hawaii is arguably the most popular such island chain, though Surtsey off the coast of Iceland is a newer example, and has the distinction of being a UNESCO protected site, since its spectacular birth in the 1960s.

*Island residents can be as fascinating as the islands themselves. The Galapagos Islands are home to a wide variety of species, even though research shows they were never connected to the mainland. That means everyone’s an immigrant, from the California sea lion, to Caribbean pink flamingo, to South American giant tortoise. Meanwhile, 1 in every 6 humans in the world live the island life, with Java sporting just under 150 million people -- nearly 2% of the global population.

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