Light is the fastest thing there is. So why does light from the nearest star take over four years to get here — and what does that say about how big space actually is?

Some nights the Moon is a fat circle. Some nights it's a thin fingernail. The Moon never actually changes shape — so what are you really looking at?

Everyone says astronauts float because there's no gravity up there. Earth pulls on the space station almost as hard as it pulls on you — so that can't be it. Here's what's really going on.

A leap year every four years — except 1900 wasn't one, 2000 was, and 2100 won't be. The rule has three parts, and the reason why is a quarter of a day that refuses to be a quarter.

The night sky is dark. Obviously. But work out how much starlight should be arriving and the answer comes out blinding — so the darkness is telling you something enormous about the universe, and it took three centuries to hear it.

Nobody has been to a star and nobody ever will. So how can anyone say the Sun is mostly hydrogen? Not by guessing — by reading the gaps in its light, which turn out to be a signature you cannot fake.

You go for a drive at night and the Moon comes too. It stays right outside your window the whole way. It is not chasing you — and there is a way to prove it.