Pet dogs and elephants are the only animals that seem to instinctively understand human gesture.
14
Mars had an oxygen-rich atmosphere around 4 billion years ago
13
The focusing muscles of the eyes move around 100,000 times a day. To give your leg muscles the same workout, you would need to walk 80km (50 miles) every day.
21
There is a mass reservoir of water floating in space that is 100,000 times bigger than our sun and holds 140 trillion times more water than all of our oceans.
11