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
In the last 7 years, humanity has discovered 43 potentially habitable planets.
14
A lump of pure gold the size of a matchbox can be flattened into a sheet the size of a tennis court.
140
An unprotected human can survive up to 1.5 minutes in space with no permanent bodily damage.
82
Pet dogs and elephants are the only animals that seem to instinctively understand human gesture.
14