Should we be worried about a bridge collapsing or a shark attack? Megan Daum runs the numbers:

Based on estimates from the National Highway Traffic Safety Administration, there were about 3,500 automobile-related deaths during that monthlong period. U.S. cancer deaths hover around 42,000 a month. As for heart disease, the American Heart Assn. tells us that someone dies of cardiovascular disease every 36 seconds. And that's just in this country.

As staggering as these numbers are, they don't seem to scare or interest us nearly as much as things like plane crashes, mountain lion attacks, deadly roller coaster mishaps or avian flu. And because the news media is savvy about (and complicit in) our fears and fascinations, we are fed an endless supply of death news that has little to do with how most people actually die. Nonetheless, death by falling asteroid seems infinitely more real than death by cholesterol.

With my luck an asteroid would hit me while I was crossing one of those structurally deficient bridges.