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
An unprotected human can survive up to 1.5 minutes in space with no permanent bodily damage.
82
There are so many kinds of apples that if you ate a new one everyday, it would take over 20 years to try them all.
34
Pet dogs and elephants are the only animals that seem to instinctively understand human gesture.
14
In the last 7 years, humanity has discovered 43 potentially habitable planets.
14