Researchers in Spain and Japan tested a broad range of pedestrians in varying group sizes to see whether there were any patterns in their turning behaviors, and what factors influenced them, if any. It ...

The Twin Paradox, explained visually: a tour through Einstein's special relativity, time dilation, length contraction, the Lorentz boost, and the relativity of simultaneity, and how they allow time travel into the future. We derive everything from scratch…