When air traffic picked up in the 1920s, pilots were left to navigate on their own, then others started to step in.

If you visit one of the 28 Major League ballparks that have deployed beacons, your smartphone can guide you to your seat or give you a customized coupon to the team store. The Metropolitan Museum of ...

Let’s say we had a way to distribute beacons around our solar system (or beyond) that could survive for billions of years, recording what our civilization has achieved. What should they be like? It’s ...