Clocks are at the heart of GPS. Advances in space-qualified atomic clocks that kept time to within 10 nanoseconds over a day were a key development that made GPS possible. It turns out that GPS must ...

The Terrell-Penrose effect, predicted in 1959, suggests that objects moving at speeds close to that of light appear rotated. This optical illusion results from the combination of relativistic length ...

Imagine watching a spaceship zoom past at unimaginable speeds—so fast it is brushing up against the very limits of physics. What do you think it would look like? Scientists have long known that ...

The idea was first hypothesized about 70 years ago. In a bizarre repercussion of Albert Einstein's Special Theory of Relativity, objects traveling close to the speed of light appear flipped over. The ...

Some habitable worlds orbiting dead stars could be kept alive for aeons thanks to a quirk of Einstein’s theory of gravity ...