Why did physicists at the beginning of the 20th century feel they needed a new — and strange — theory?

Here's a quick introduction to the most famous cat in the history of science. We hope it whets your appetite for quantum mechanics!

A very strange way of explaining away the strangeness of quantum mechanics.

At the heart of modern physics lurks a terrible puzzle: the two main theories that describe the world we live in just won't fit together.

A closer look at one of the simplest quantum algorithms.

Quantum computers often grab the science headlines. But what exactly is quantum computing? What will quantum computers be able to do, and when can we expect to have fully functional ones?

An untapped resource could provide the magic needed for quantum computation — and perhaps even open the door to time travel.

Here's a brief introduction to the possible future of computing.

Observers are, of course, vital in physics: we test our theories by comparing them to our observations. But in cosmology, as Jim Hartle explains, we could be one of many possible observers in the Universe and knowing which one we are is vital in testing our theories.

Why does time have a direction?

To create energy from information you would need to break the second law of thermodynamics — that's impossible in the real world, but could theories that do break it shed light on why nature is the way it is?

Are there objective chances in the world?