A concept long confined to myths, philosophy, and science fiction is quietly finding its way into serious scientific discussion. While no human has stepped into the past or the future, new research ...

“Time flies,” “time waits for no one,” “as time goes on”: The way we speak about time tends to strongly imply that the passage of time is some sort of real process that happens out there in the world.

Time feels like the most basic feature of reality. Seconds tick, days pass and everything from planetary motion to human memory seems to unfold along a single, irreversible direction. We are born and ...

Thanks to Einstein’s relativity, time flows differently on Mars than on Earth. NIST scientists have now nailed down the difference, showing that Mars clocks tick slightly faster—and fluctuate over the ...