NASA sees giant crack forming in Antarctic glacier

NASA scientists are watching a giant crack forming over a vulnerable Antarctic glacier and they think it will soon break off into an iceberg the size of New York City.

Experts said they noticed the crack on Oct. 14 while mapping Antarctica's Pine Island Glacier with a low-flying plane. The crack is about 18 miles (29 kilometers) long and averages about 260 feet (80 meters) wide. Scientists say it is growing about 6 feet (1.8 meters) wider each day.

The Pine Island Glacier is called "the weak underbelly of Antarctica," and it is thinning. But scientists say this type of cracking happens naturally every decade and is not related to global warming. They said the new iceberg could break away by the end of this year or early in 2012.