General relativity stands as one of the bedrock theories in modern physics. Its strange view of relative time and space has been confirmed by countless experimental and observational tests, from ...

No audio available for this content. Image: GPS.gov 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 ...

In 1905, a 26-year-old patent clerk named Albert Einstein looked at the universe and discovered that time was not what we thought it was. It was not linear. For centuries, everyone assumed the same ...

Light released by a distant star does not simply wink out after crossing some threshold of space. In a vacuum, photons keep ...