Few ideas in modern science have reshaped our understanding of reality more profoundly than space-time—the interwoven fabric ...

Once space and time themselves are flexible rather than fixed, what else is left that we can say is truly constant? There is one obvious candidate, again from Einstein himself: the speed of light.

What is space-time? Depending on how fast you're moving or how close you are to Earth's gravity can change the way time feels.

Natalie Paquette spends her time thinking about how to grow an extra dimension. Start with little circles, scattered across every point in space and time—a curlicue dimension, looped back onto ...

An ambitious new fleet of spacecraft could reveal whether space-time is smooth or chunky, and in doing so the ultimate nature of reality.

Time always passed at the same rate, and was absolute as well. To any observer, particle, wave or quantum anywhere, they should experience space and time exactly the same as one another.