Much has been made about the “impending” end of the world in 2012, but NASA assures us that this is much ado about nothing. While Hollywood and the Mayan calendar suggest that Dec. 21, 2012, will be the end of all things, NASA expects that the date will pass much like the Y2K scare — without so much as a whimper. It appears the agency is taking a “nothing to see here” approach. And yet, one day, the world will end. Most experts believe our sun will eventually supernova in 5 billion years or so, taking much of our part of the solar system with it. But there are other ways life on Earth — or in some cases, the Earth itself — might be destroyed. Here are seven ways that might happen. (Text: Katherine Butler)