Cambridge students attached a camera to a balloon and let it float up, up, and away. Wistful? Childish? Nope, it's Project Nova, the first step of these students' dreams of building rocket ships that will go into space.

Wistful and childish still? Not really. Their little experiment achieved two very important things:

• It reached about 20 miles above the surface of the earth - high enough to see the Earth's curvature.
• It was done for less than a thousand pounds.