Iron weighs more after it rusts.
68
Stephen Hawking once tried to find potential time travellers by throwing a party and only sending out invitations after the party.
17
It takes a photon 170,000 years to travel from the core of the Sun to the surface, but only 8 minutes to travel the rest of the way to Earth.
6
Nearly 50% of the world's scientists are assigned to military projects.
71
Marie Curie, the Nobel prize winning scientist who discovered radium, died of radiation poisoning.
57
Every day, plants convert sunlight into energy equivalent to six times the entire power consumption of human civilization.
9
A coal power station puts 100 times more radiation into the air than a nuclear power plant producing the same amount of energy.
7