Why did Uuq become Fl?

Why is the sky blue? Why is the sky black?

What is spaghettification?

There's a problem with the typical quiz. It always features far too much sport, 1980s pop and celebrity gossip – and not nearly enough science.

How Many Moons Does the Earth Have? is the ultimate solution. Test your knowledge to the limit with a sizzling collection of brain-stretching, science-based questions in two eight-round quizzes.

Turn the page to get the answer immediately – and as each answer page explores the subject in more depth, this the only quiz that's just as entertaining to read from beginning to end as it is to play competitively.

Where was the Big Bang? What links the elephant Tusko and Timothy Leary? What is the significance of 6EQUJ5? Science explainer extraordinaire Brian Clegg tells all…