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 3:03pm10/09/14 3:03pm

How Quantum Theory Screws With Our Perception of Reality

Our modern understanding of reality is based on some fundamental concepts: that the world around us is tangible, that the theory of relativity holds, that cause and effect works as we'd expect, and that humans have free will. But take quantum theory at face value, and it turns out the four can't co-exist together. »8/08/13 4:43am8/08/13 4:43am

NASA Gravity Experiment Proves Einstein Was Right

Like a beach chair sagging under a sunbather's weight, the fabric of spacetime does indeed warp around the mass of the Earth - just as Albert Einstein predicted. And like a swimmer moving through the water, the rotation of the Earth affects the movement of spacetime itself. A gravity probe whose origins date to the… »5/05/11 10:40pm5/05/11 10:40pm

This Animated Video Simplifies Einstein's Complicated Twin Paradox

Einstein's Twin Paradox is super confusing for me, every time I think I fully understand it, I find more questions. The Twin Paradox is a thought experiment in special relativity when one twin travels to outer space while the other twin stays on Earth. When the space bound twin lands back on Earth, he'll find that… »2/20/11 4:00pm2/20/11 4:00pm