The units of time are firmly connected with astronomical phenomena and processes occurring with the Earth, for example, its rotation around its axis, around the Sun, the rotation of the Moon around the Earth, etc. All these orbital movements determine the presence of day and night, the change of seasons and the unity of the passage of time as a whole. Since every day the sun rises and sets over the horizon, it was customary to divide them into two parts - day and night, each of which divided into 12 equal parts - hours. Further, according to the six-decimal system, the hour was divided into minutes, minutes into seconds. In the international SI system of units, the main unit of time is the second. The duration of a sunny day during the year deviates from the average by a fraction of a second. Therefore, the Julian day was introduced, equal to 86,400 exactly, and, accordingly, the Julian year, also called the scientific year. The accumulated "extra seconds" form every 4 years an extra day in the Gregorian year - February 29. How to use the time converter: If you want to know how many seconds are in 1 hour, indicate 1 in front of the line “Hour” and press Enter. The system will automatically calculate the number of seconds, minutes, and other time units in an hour. To calculate how many hours are in 30,000 seconds, indicate this number in the “Second” line and do the same.