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?

How understanding why something is impossible can often lead to deeper understanding, contemplations of philosophy and even new mathematics.

Yes, it does. And we have the maths to prove it.

What is infinity? Does it even exist? And how many infinities are there?

No one really knows the answer to this question. It's quite possible that there are more than one, in fact there may be infinitely many, popping in and out of existence like bubbles in a bubble bath.

Does time have a beginning? Is it possible to travel through time? And what does it mean to say that time is relative?