To celebrate the release of more English translations of Einstein's papers, we revisit one of his previously unknown models of the Universe.

Where planets are born is not necessarily where they will stay…

Anything involving bunny rabbits has to be good.

A Klein bottle can't hold any liquid because it doesn't have an inside. How do you construct this strange thing and why would you want to?

How to write a sum that's infinitely long.

What is 1-1+1-1+1-1+...? How infinite sums challenge our notion of arithmetic.

Here's an easy game that leads you straight to an unsolved question in maths.

How to write down unimaginably large numbers using just a few symbols.

A little trig helps to find the relative distance to the Sun and Moon.

Bob Wald tells us why probabilities are important in cosmology.

Why maths is an important tool in the fight against Ebola.

Why do we add fractions the way we do? A very close look at addition reveals the answer — and it also works for negative numbers.