Picture a volcano. Now imagine that its main vent extends in a line. Now imagine that this line is so long that it runs for more than 40,000 miles through the dark recesses of all the world’s oceans, girding the globe like the seams of a baseball.
Welcome to one of the planet’s most obscure but important features, known rather prosaically as the midocean ridges. Though long enough to circle the moon more than six times, they receive little notice because they lie hidden in pitch darkness. Oceanographers stumbled on their volcanic nature in 1973. Ever since, costly expeditions have slowly explored the undersea world, which typically lies more than a mile down.
The results can make the visions of Jules Verne seem rather tame.
The ridges feature long rift valleys and, down their middles, giant fields of gushing hot springs that shed tons of minerals into icy seawater, slowly building eerie mounds and towers that can be rich in metals like gold and silver. One knobby tower in the Pacific Ocean, nicknamed Godzilla, grew 15 stories high. Thickets of snakelike tubeworms and other bizarre creatures often blanket the hot features, as do hungry prowlers such as spider crabs.
The riot of life coexists with springs hot enough to melt lead or the plastic windows of mini submarines. With extreme care, humans and robots have measured temperatures as high as 780 degrees.
To date, the studies have been episodic. Ridge expeditions venture out fitfully, their schedules determined by fickle weather and budgets, not to mention the vagaries of crew and gear availability.
Now, scientists have inaugurated a major new effort.