http://www.buzzfeed.com/tomchivers/slippin-slippin-slippin-into-the-future#.eslQa2Yyn 1. Time passes faster for your face than for your feet (assuming you’re standing up). Einstein’s theory of relativity dictates that the closer you are to the centre of the Earth, the slower time goes – and this has been measured. At the top of Mount Everest, a year would be about 15 microseconds shorter than at sea level. 2. A second isn’t what you think it is. Scientifically, it’s not defined as 1/60th of a minute, but as “the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom”. 3. What you think of as a day – how long it takes the Earth to rotate – isn’t 24 hours. It’s 23 hours, 56 minutes and 4.2 seconds. The reason it’s 24 hours from sunrise to sunrise is because every day the Earth moves further in its orbit round the sun – and the change in its position lengthens the day slightly. More at the link.