Stephen Hawking once tried to find potential time travellers by throwing a party and only sending out invitations after the party.
17
Scientists have developed a microparticle filled with oxygen that can be injected into the blood stream, enabling us to live without breathing.
21
A single speck of dust is half way in size between a subatomic particle and the Earth.
15
One 75-watt bulb gives more light than three 25-watt bulbs.
57
In zero gravity, a candle's flame is round and blue.
16
Indoor pollution is 10 times more toxic than outdoor pollution.
62
One ragweed plant can release as many as one billion grains of pollen!
51
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