Example image of eyePlorer eyePlorer map for 'Second': International System of Units SI base unit Time Units of measurement Atomic clock Microsecond Millisecond Nanosecond SI prefix 1 E3 s Hour Minute Centimetre gram second system of units Imperial units Metre-tonne-second system of units MKS system of units Absolute zero Caesium Gravitational time dilation Kelvin Magnetic field Ephemeris time ISO 31-1 National Institute of Science and Technology National Research Council (Canada) Free space Lamb shift Vacuum state Virtual particle Ampere Metre Day International Astronomical Union Julian year (astronomy) Leap second Hellenistic civilization Hipparchus Ptolemy Sexagesimal Babylonia Hebrew calendar Helek Abu Rayhan Biruni Persian people Roger Bacon Arabic language Polish language Turkish language Istanbul observatory of Taqi al-Din Taqi al-Din Muhammad ibn Ma'ruf