... What is the notion time? ... Generally speaking, it is an order of changing events, an order of constantly changing conditions of solids, Universe - being. ... The time, determined for the given longitude, is called the local time . ... A uniform system of time counting - ephemeris time is tested by observations of the Moon turning around the Earth. Fully independent from astronomic observation uniform system of the time counting is based on the concept of atomic second (see quantum watches ). ...