Icebergs are really big, really cold, really beautiful, really dangerous, and really important.
HOW BIG IS AN ICEBERG?
Picture an ice cube about the size of Connecticut. That’s the size of B15, the iceberg that broke off Antarctica on March 17, 2000. At 183 miles long and 25 miles wide, this massive berg—nicknamed Godzilla—rose 120 feet above the ocean’s surface and bottomed out at a depth of 9,000 feet below, and weighed in at around four trillion tons!
WHERE DO ICEBERGS COME FROM?
Snow is almost constantly falling on the ice sheets of Antarctica (southern hemisphere) and the glaciers of Greenland and Canada (northern hemisphere). All of this snow gets packed down under its own weight and slowly slides toward the sea. When the compacted snow reaches the water’s edge—usually after thousands of years—it forms a huge ice “shelf.” Then cracks develop from the combination of more ice sliding down behind it and ocean waves battering the front of it. When one of these cracks gets large enough, a huge chunk of ice breaks off into the sea. That’s when it becomes an iceberg.
As soon as it hits the ocean, the iceberg starts to melt—bigger bergs have been known to last up to two years in colder waters. In the meantime, ocean currents and wind can carry an iceberg thousands of miles. This can be especially hazardous in the North Atlantic, where icebergs frequently cross shipping lanes. That’s what sank the Titanic in 1912.
Sapphires and rubies are chemically identical in every way…except for their color.
You’d think that something that weighs trillions of tons would immediately sink to the ocean floor—but ice doesn’t. Most substances shrink when they cool, but when water turns into ice, it expands. For an object to float, it has to weigh less than the amount of water it displaces, so because ice is less dense than water, it floats. But not all of it—between 70% and 90% of it is under water. (Try it yourself: drop an ice cube in a glass of water and see how much of it is below the surface.)
WHY ARE ICEBERGS IMPORTANT?
Scientists use icebergs to measure global warming. As Earth’s temperatures slowly rise, some environmentalists speculate that the glaciers will break apart faster, causing more icebergs to fill the seas, and causing sea levels to rise. If the levels rise high enough, you’ll need a boat to travel through New York City.
Other scientists believe that the massive amounts of fresh water contained in icebergs could be used to quench thirst and irrigate farms around the world. The B15 iceberg, for example, could have supplied the entire United States with water for five years—if only we knew how to extract it. The problem is that towing a million- or billion-ton iceberg is very expensive. Some Middle Eastern nations have considered transporting huge icebergs from Antarctica to the Persian Gulf, but most of the ice would melt before it reached its destination.
Picky, picky: A year is actually 365 days, 5 hours, 48 minutes, and 46 seconds long.
• The process of glacial ice cracking and falling into the sea is called calving.
• Icebergs come in many shapes and sizes:
Brash ice are tiny icebergs. They can be as small as an ice cube or as big as a baseball.
Bergy bits are icebergs that are larger than baseballs and smaller than beach balls.
Growlers range from 3 feet to 10 feet. Why are they called growlers? Because sailors often hear a growling sound as they bob up and down in the water.
Bergs are the large icebergs, the largest of which are called tabular bergs. Found only in the Antarctic, they’re formed when huge plates of ice break off of the ice shelf; B15 was a tabular berg.
• Most of an iceberg is under the water, so when someone says, “It’s only the tip of the iceberg,” they mean there’s a lot more to the story than what’s being told.
There are no thunderstorms in polar regions. Why? Not enough warm air.