A Brief History of Scientists Hunting for Time Travelers

Time travel is possible—or at least a lot of serious physicists say so. It's probably not possible to pull it off in a souped-up Delorean, but there are wormholes, Tipler cylinders, and other Einstein-inspired theories for how it could work. Which raises the question: Why haven't we met any visitors from another time? » 10/09/14 3:39pm 10/09/14 3:39pm

What Memories Of Yours Should Be Recorded For Historical Purposes?

Written histories tend to focus on a few large stories, but those stories are actually made up of hundreds of smaller stories that come from the people who witnessed or were part of events as they happened. So what stories and memories do you have that should be preserved as part of the historical record? » 9/29/14 7:00am 9/29/14 7:00am

What Most Freaks Out Scholars Who Study The Future Of Humanity?

It's only Tuesday, but already this week's news is apocalyptic: the collapse of the West Antarctic Ice Sheet is unstoppable, the UN is debating whether to ban killer robots and the U.S. and Russia are going 1980s-retro with nuclear war games. What should worry us the most? Here's what two experts think. » 5/13/14 6:30am 5/13/14 6:30am