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
In zero gravity, a candle's flame is round and blue.
16
4.5 pounds of sunlight strike the Earth each day.
27
Pumice is the only rock that floats on water.
14
Your brain is 80% water.
525
The brain case [of Neanderthals] on the average was more than 13 percent larger than that of the average of modern man
61
Indoor pollution is 10 times more toxic than outdoor pollution.
62