Did Romans really purge their bellies in vomitoria?

Oh, the hallowed Roman vomitorium -- a disgusting symbol of the Romans' wealth and excess. When they discovered that their bellies had become too full to eat another bite, they could simply excuse themselves from the table, visit a nearby vomitorium to purge and then return to the feast. The vomitorium, far from being gross, was common in polite Roman society.

How can you tell if you're mentally ill?

Mental illness is a term that comprises many different conditions, from anxietyand mood issues to addictions and psychotic disorders. We may think that these illnesses are rare, or things that simply happen to other people. We may think that they'll be easy to spot, thanks to dramatized depictions of them in film and television. We might not be willing to consider that we could have a mental disorder ourselves.

What will Earth look like in 500 years?

If you could travel back in time five centuries, you'd encounter a thriving Aztec empire in Central Mexico, a freshly painted "Mona Lisa" in Renaissance Europe and cooler temperatures across the Northern Hemisphere. This was a world in the midst of the Little Ice Age (A.D. 1300 to 1850) and a period of vast European exploration now known as the Age of Discovery.

What if you never aged?

Flamboyant pop music icon Prince celebrated his 53rd birthday in 2011. Yep, you read that right. Our planet has experienced decades of "Purple Rain," and no matter how old and busted that makes you feel, it's clear that Prince's genes didn't get the memo. The man looks as youthful as ever. Will he ever age? And if he does, will he ever die?

Do dire wolves exist?

Confession: When I was somewhere north of 20 years old, I was on a beach somewhere in Virginia, attempting to explain to my brother and sister-in-law why it was so weird that the University of Michigan's mascot was the wolverine. It was like having a unicorn for a mascot, I said. Or a jackalope -- that mythical half-rabbit/half-antelope that adorns stupid postcards in the West. They weren't getting it and kept on insisting it really wasn't like that at all. Finally, I had to ask point-blank: Were they saying that wolverines were ... real?

Do daddy longlegs really have powerful venom?

A lot of us were taught to be kind to daddy longlegs. The gangly spiders that hung out around the house and seemed to mind their own business didn't do much to warrant shrieking or stomping on, in general. But others heard a much more pernicious tale: Daddy longlegs actually possess powerful venom. Often, it was said that the only thing stopping them from killing us all in our sleep was that their short little fangs couldn't properly puncture skin. Seem unbelievable?

Why can't we convert salt water into drinking water?

It seems strange that water should be such a scarce resource when our planet is drenched in 326 million trillion gallons of the stuff. But it turns out that less than one-half of 1 percent of it is drinkable. Out of the rest, 98 percent is oceanic salt water and 1.5 percent remains locked up in icecaps and glaciers. The stark irony of Samuel Coleridge's immortal line "Water, water, everywhere / Nor any drop to drink" is manifest each year in coastal disasters around the world, like Hurricane Katrina, the 2004 Indonesian tsunami and the 2010 Haiti earthquake, as people within sight of entire oceans are threatened with dehydration.