Leap Second is a series of artworks showing the 24 leap seconds that have been added to our time so far. Leap seconds are added occasionally due to the earth gradually slowing down, primarily due to the tides. This slowing can not be predicted, but its effect means our time gradually goes out of sync with the position of the sun. Leap Second, 30 June 1972 - 23:59:60 is the first leap second, 78796800 in unix time.­