For centuries mariners have told stories about sudden waves that would emerge out of the open ocean without warning, strong enough to topple even large ships. The SS Waratah, which vanished on a journey to Cape Town; the MS Munchen, lost en route to Savannah; even the SS Edmund Fitzgerald, "the good ship and true" of the Gordon Lightfoot song, which disappeared on Lake Superior — all were rumored to be sunk by rogue waves.
Until recently, however, marine scientists dismissed rogue waves as little more than a sailors' fantasy, with reason — there was little evidence to back them up. But in 1995 an oilrig in the North Sea recorded a 25.6 m-high wave that appeared out of nowhere, and in 2000 a British oceanographic vessel recorded a 29 m-high wave off the coast of Scotland. In 2004 scientists from the European Space Agency (ESA), as part of the MaxWave project, used satellite data to show that freak waves, higher than 10 stories, were rare but did occur on the oceans.
Scientists still don't know exactly how rouge waves occur, nor do they know how to predict them. Open ocean waves, possibly including rogue waves, form when wind produces distortion over the surface of the sea — the stronger the wind, the higher the wave, which is why hurricanes can create such destructive walls of water. Tsunamis, on the other hand, like the one produced by the 8.8-magnitude earthquake in coastal Chile on Feb. 27, don't create rogue waves; tsunamis barely make a ripple on the open ocean, and only gather in size when they reach shallow land near a coastline. (See TIME's special report on the environment.)
Rogue waves generally occur out in the open ocean. They may be the result of a number of factors coming together — strong winds and fast currents coinciding, for instance — or of a focusing effect, where several smaller waves join together to form one big wave. There may even be a non-linear effect at work, in which just a small change in wind speed multiplies to form a big wave. And certain areas of the ocean, like the strong waters off Africa's coast, may be more vulnerable to rogue waves than others.
Creating artificial rogue waves in a laboratory has always been a challenge. But in 2009, scientists from Harvard University and Tulane University examined patterns of microwaves, rather than water waves, to get a better sense of how rogues might arise. They created a metal platform in a lab measuring 26 cm by 36 cm, and randomly placed 60 small brass cones on the platform, to mimic the effect of unexpected ocean eddies in the current. When they beamed microwaves at the platform, the scientists found that "hot spots" — the microwave equivalent of rogue waves — appeared as much as 100 times more often than standard wave theory would predict. Those results indicate that rogue waves might be a lot more common than scientists had believed, and could explain why so many large ships — as many as two a week — sink even in the absence of bad weather. One day we might even be able to predict when these earthquakes of the sea occur — sparing future cruisegoers from the trauma suffered by those on the Louis Majesty.
http://www.time.com/time/health/article/0,8599,1969845,00.html?xid=rss-topstories
