SPACE.com -- Dramatic Comet Outburst Could Last Weeks

SPACE.com -- Dramatic Comet Outburst Could Last Weeks: "comet that suddenly brightened earlier this week has astronomers around the globe fascinated. And the show could go on for some time. Comet Holmes, discovered in 1892, had in recent years been visible only through telescopes until a dramatic outburst made it visible to the naked eye. In fewer than 24 hours, it brightened by a factor of nearly 400,000."