Scientists can show that the moon is moving away at a tiny, yet measurable, distance from Earth every year.
If you do the maths, you can calculate that 85 million years ago, the moon was orbiting Earth at a distance of about 10 metres from the Earth's surface. And this explains the extinction of the dinosaurs. The tall ones, anyway.
A Russian, an American, and a Cambridge science graduate are talking one day.
(Replace 'Cambridge' with your rival university name)
Russian: "We were the first in space!"
American: "We were the first on the moon!"
Cambridge: "So what? We're going to be the first on the Sun!"
The Russian and American look at each other, slowly shaking their heads.
Russian: "You can't land on the Sun, you silly man, you'll burn up!"
Cambridge: "We're not stupid, you know. We're going at night!"