On one hand, the speed of light is just a number: 299,792,458 meters per second. And on the other, it’s one of the most important constants that appears in nature and defines the relationship of ...

Add Yahoo as a preferred source to see more of our stories on Google. The universe has a speed limit, and it's the speed of light. Nothing can travel faster than light — not even our best spacecraft — ...

Everyone knows the number for the speed of light — but almost nobody knows the uncomfortable truth behind it. Measuring light in one direction requires perfectly synchronized clocks, and that’s the ...