Introduction
Like the complex and mysterious problems of the origin of the solar system and the earth, there is a lot of difference of opinions about the age of the earth and its past geological history. Various scientists have attempted to calculate the age of the earth on the basis of different scientific basis, experimental researches and logical arguments but their findings, results, and conclusions are so varied and contrasting that it becomes very difficult to arrive at a convincing conclusion which may be acceptable to the majority of the scientific community. In fact, it is a quite difficult task to find out the exact time of the origin of the earth and the periods of its evolutionary stages.
It may be argued that geological processes work so slowly that no one can observe them fully during one's lifetime.This is why Scottish geologist James Hutton opined in 1775 that 'the earth's surface undergoes frequent changes but these changes consume such a long time that it becomes difficult for the man to find out the dates of such changes.' In fact, the dating of the past geological events is 'wild catting' as there is 'no vestige of a begnning, no prospect of an end' (James Hutton). Inspite of the fact that no universally acceptable method could be evolved till now to calculate the age of the earth and its geological events, several methods and concepts have been propounded from time to time and are still being proposed to unravel the mystery of the earth's history.
Religious Concepts
Serious efforts have been made since time immemorial by the religious priests, philosophers and astrologers to calculate the age of the earth. Old Iranian religious priests calculated the age of the earth as 1200 years while Archbishop Usher of Iceland in 1664 maintained that the earth was created at 9.00 A.M. October 26, 4004 B.C. (presum-ably Greenwich mean time) but these concepts cannot be accepted because these only make a fun of the age of the earth. According to Indian religious records the age of the earth has been determined as 2 billion (2000 million) years.
Indian religious experts have calculated the age of the earth on the basis of the interpretation of the above statement as 1,972,949,032 years (about 2.0 billion years). This calculation is based on guess work and deduction but it nearly matches with the calculations based on scientific and mathematical methods but the result (2 billion years) is not closer to commonly accepted age of the earth (4 to 5 billion years).
On the basis of oceanic salinity
Present-day oceanic waters contain salt content but it is believed that the oceans at the time of their creation would have contained pure water, that is water without salt content. Later on rainwater after passing through continental surfaces removed salt contents from the land areas due to subaerial erosion and thus terrestrial salt used to reach the oceans through the rivers and thus oceanic water began to become saline. With the passage of time oceanic salinity continued to increase. It has been generally established on the basis of experiments and observations that about 60 per cent of sodium of the oceanic salt is contributed by the rivers. It has also been demonstrated that there is more or less similarity between the oceanic salt and the salt brought down by the rivers. It has been believed on this basis that rivers are the major source of oceanic salinity. Thus, there is gradual increase in the oceanic salinity because of deposition of terrestrial salt by the rivers in the oceans every year. If the total amount of oceanic salt is known and if the annual rate of increase of oceanic salinity is determined, the age of the oceans may be calculated and determined.