Carbon dating is a widely utilized method employed to determine the age of organic materials, essentially things that were once alive. This method is founded on the fact that Carbon-14 (C-14) is radioactive with a well-known decay rate. Carbon-14 is an isotope of carbon alongside the most abundant isotope, Carbon-12 (C-12). C-12 and C-14 are absorbed in roughly equal proportions by plants during photosynthesis and by animals through food. Upon death, the interaction with the atmosphere ceases and while C-12 remains stable, the radioactive C-14 reduces to half its original quantity every 5,730 years or so. This period is known as its ‘half-life’. The changing ratio of C-12 to C-14 can be measured and used to decode the approximate time of death.
Age Determination of Inanimate Things
The carbon dating method does have limitations. It cannot be applied to non-living things such as rocks. Additionally, anything older than 40,000-50,000 years cannot be accurately dated using this method due to the minuscule and nearly undetectable amount of C-14 left after 8-10 cycles of half-lives. In these cases, Radiometric Dating Methods, which rely on the decay of other radioactive elements present within the material, are used. These techniques involve elements with half-lives spanning billions of years, enabling scientists to estimate the age of very old objects reliably.
Radiometric Methods
Two prevalent methods for dating rocks include Potassium-Argon and Uranium-Thorium-Lead dating. With Potassium-Argon dating, the radioactive isotope of potassium decays into argon, and the ratios can indicate the age of rocks. Similarly, uranium and thorium have several radioactive isotopes that decay into the stable lead atom. The ratios of these elements can be used to estimate age. There are also methods to determine how long an object has been exposed to sunlight, such as cosmogenic nuclide dating. This is particularly useful in studying buried objects or changes in topology.
Indirect Carbon Dating
Carbon dating can also be employed indirectly to determine the age of ice cores in glaciers and polar regions by analyzing carbon dioxide molecules trapped within the large ice sheets. These trapped molecules are found in the same state as when they were trapped, with no interaction with the outside atmosphere.
Limitations of Determining Age of Gyanvapi Shivling
In the recent case of the Gyanvapi Mosque in Varanasi, Uttar Pradesh, the conventional methods of age determination may not be feasible due to specific limitations that prevent disruptive methods or uprooting of the structure.
The Gyanvapi Dispute
The Gyanvapi dispute centers around the Gyanvapi Mosque complex, where it is claimed by Hindu petitioners that the mosque was constructed on the site of an ancient Hindu temple. The claim is primarily substantiated by the presence of a “Shivling” inside the mosque. However, the management committee of the mosque counters that the land is Waqf property and argues that The Places of Worship Act of 1991 prohibits any alterations to the character of the mosque. The mosque was built during the reign of Mughal emperor Aurangzeb, in 1669, post demolition of the existing Vishweshwar temple. Subsequently, the Kashi Vishwanath Temple, dedicated to Lord Shiva, was constructed adjacent to the mosque in the 18th century. The controversy persists as claims continue to assert that the mosque remains the original sacred place of Hindu worship.
