Can a single particle have a temperature? It may seem impossible with our standard understanding of temperature, but columnist Jacklin Kwan finds that it’s not exactly ruled out in the quantum realm ...

Most physicists doubt that time exists. On this page 40 years ago, we published scientific ‘proof’ of time being illusory. We pointed out that none of the equations of physics, from Newton’s laws to ...

For nearly a century, astronomers have watched galaxies spin and the universe expand in ways that visible matter alone cannot ...

The “Theory of Everything” is the dream of physics — one framework that connects gravity, quantum mechanics, space, time, and ...

Scientists pushed photons across the universe to test the speed of light—and found Einstein’s cosmic speed limit still holds firm.

This puzzle is known as the problem of time, and it remains one of the most persistent obstacles to a unified theory of ...

The second paper, "Fermion Chirality from Non-Bipartite Topology," applies this same lattice geometry to the quantum world. It proposes that the "handedness" (chirality) of subatomic particles is not ...

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 ...

A hundred years ago this week, at the height of the quantum revolution, Austrian physicist Erwin Schrödinger submitted a ...

Cosmic strings and Einstein’s relativity raise the theoretical possibility of time travel within modern physics.

Instead of the big bang, some physicists have suggested that our universe may have come from a big bounce following another universe contracting – but quantum theory could rule this out ...