Physics

The crisis inside the physics of time.

In the fundamental physics of the world, there is neither space nor time.

A theoretical physicist challenges our common notions about the fourth dimension.

Two ways of measuring the universe’s expansion rate yield two conflicting answers. Many point to the possibility of new physics at work, but a new analysis argues that unseen errors could be to blame.

Nine letters by Freeman Dyson portray his relationship with the Nobel Laureate.

A recent experiment shows how quantum mechanics can make heat flow from a cold body to a hot one, an apparent (though not real) violation of the second law of thermodynamics.