The average temperature at 40,000 feet above sea level is -60 F.
56
In Arizona, a solar wind energy tower has been proposed that would generate as much energy as the Hoover Dam.
5
Iron weighs more after it rusts.
16
Nearly 50% of the world's scientists are assigned to military projects.
71
The Earth's atmosphere weighs about 5.5 quadrillion tons.
108
A single speck of dust is half way in size between a subatomic particle and the Earth.
15