The Earth's atmosphere weighs about 5.5 quadrillion tons.
108
Kissing actually has the biological purpose of passing on biological information and chemical signals to assess mating possibilities and status.
9
Nearly 50% of the world's scientists are assigned to military projects.
71
Airports that are at higher altitudes require a longer airstrip due to lower air density.
39
Your brain is 80% water.
525
Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
Only 12,000 years ago there was a species closely related to modern humans called Homo floresiensis that had been living on an Indonesian Island. They used fire and rather advanced tools, yet were only about 3 feet tall and weighed around 25kg.
15