When you move beyond trillions, there are some extremely mind-bending numbers, says Richard Fisher. Some of them are too large to fit in the mind – or even within the known Universe. What's the ...

Imagine Earth were to shrink to the size of a marble. We might be in trouble, but the planet would continue its smooth course around the sun while the moon would maintain its orbit, circling Earth ...

Think of a Number presenter Johnny Ball explains the concept of infinity to four-year-old Claudia Haworth. Claudia's mother Ellie wrote into the BBC's numbers programme More or Less to ask the team to ...