Taken from the 25th anniversary issue of Physics World, this article examines one of the five biggest unanswered questions in physics as selected by the magazine’s editors Scientists and philosophers ...

What is time? If you're a practising physicist, it's a quantity in your equations, t. This is the variable that you use for one of the four dimensions of the manifold of space-time, the term ...

In physics, the treatment of time is a central issue. In physics, the treatment of time is a central issue. It has been treated as a question of geometry. One can measure time and treat it as a ...

What Is The Time? The concept of time feels so natural that we often forget just how peculiar it is. What actually is time? Figuring it out remains one of the trickiest problems in physics.

But it is boring in comparison to the larger questions about space and time. Discussing what space and time are and where they came from is now within the realm of particle physics.

Deep tech Classical physics make time travel impossible. But what about ‘timeless’ travel? Where we're going... we won't need roads. Or clocks. Or speed limits.

The ability to jump forward and backwards in time has long fascinated science fiction writers and physicists alike. So is it really possible to travel into the past and the future?

Spacetime may emerge from a more fundamental reality. Figuring out how could unlock the most urgent goal in physics—a quantum theory of gravity ...