What is carbon dating, and how does the Varanasi court order impact the dispute?

Source: The post is based on the article “What is carbon dating, and how does the Varanasi court order impact the dispute?” published in Indian Express on 20th October 2022.

What is the News?

Varanasi district court has rejected the plea to conduct carbon-dating of the disputed structure known to have been found inside the premises of the Gyanvapi Mosque.

What is Carbon Dating?

Carbon dating is a widely-used method to establish the age of organic materials, things that were once living. It can be estimated by measuring the amount of carbon-14 isotope present in the subject.

How does it work?

Plants and animals get their carbon from the atmosphere, they too acquire C-12 and C-14 in roughly the same proportion as is available in the atmosphere.

Plants get their carbon through photosynthesis; animals get it mainly through food. When they die, their interactions with the atmosphere stops.

While C-12 is stable, the radioactive C-14 reduces to one-half of itself in about 5,730 years — known as its ‘half-life’.

The changing ratio of C-12 to C-14 in the remains of a plant or animal after it dies can be measured and can be used to deduce the approximate time when the organism died.

Limitations: The Carbon Dating method cannot be used to determine the age of non-living things like rocks.

Also, the age of things that are more than 40,000-50,000 years old cannot be arrived at through carbon dating.

This is because, after 8-10 cycles of half-lives, the amount of C-14 becomes almost very small and is almost undetectable.

What are the other types of dating methods?

Radiometric Dating Methods: In this method, decays of other radioactive elements that might be present in the material become the basis for the dating method.

Two commonly employed methods for dating rocks are:

– Potassium-Argon Dating: The radioactive isotope of potassium decays into argon and their ratios can give a clue about the age of rocks.

– Uranium-Thorium-Lead Dating: Uranium and Thorium have several radioactive isotopes, and all of them decay into the stable lead atom. The ratios of these elements present in the material can be measured and used to make estimates about age.