علم الزمن والوقت
There is nothing that is as much difficult in the field of science as “simplifying concepts”, and there is nothing as much harder in the research as to what seems obvious and easy in the beginning.
The second for instance, is a unit of time measurement; but what is the second according to the scientific concepts? Is it constant throughout the history? Can the second be measured with more accurate measure?
These are questions of scientific thought; and we may mention the following:
The second is one of the units of time and angles; i.e. it is a unit that combines between “place” and “time” as the common denominator is that the circle is the standard and reference in measuring angles, as well as it is the measure and reference in measuring time.
The circle has 360 degrees, each degree is divided into 60 minutes, and each minute is divided into 60 seconds.
As for time, the day is the time when the sun returns to the point from which it started, in a circular motion divided into 24 hours, each hour into 60 minutes, each minute into 60 seconds, therefore, the second is part of 24×60×60=86400 parts of the day.
Therefore, when we divide the day into 86400 parts; each part represents the second.
However, it was discovered in the middle of the previous century that the earth does not always rotate in the same speed, as it sometimes goes slower or faster even by a small proportion, but still exists, therefore, it cannot turn into a unit of measurement, but the first requirement of the measurement units is the “Isochronism”.
Hence, there was a need for more accurate reference. In 1967, within the existence of the atomic clock, which operates with cesium 133 vibrations; accordingly, the second was defined as the time it takes for a cesium atom to move between highly accurate levels, in which about 9.192.631.770 vibrations take place.
Through the atomic second, we can measure the cosmic second, which is based on movement of the sun and the earth, and know when the slowdown and acceleration take place, and how much is it?
It is known that within the scientific development, the second is divided into smaller units with large numbers, for instance, according to the International System of Units, yoctosecond = is septillionth of a second (10-24) or 10–24 s, then the zeptosecond (10-21), attosecond (10-18), then femtosecond (10-15) etc. it is known that the discovery of femtosecond was made by the scientist Ahmad Zewail, winner of the Nobel Prize in chemistry in 1999.
Dr. Mohamed Babaami
Al-Manahidj Institute
6 Rabi’ Al-Awwal 1444 A.H./ 2 September 2022 A.D.
Written by: Dr. Mohamed Babaami
Translated by: Toufik Achour
Date:05/08/2023 The Article title in Arabic: الثانية الزمنية
