Ask a geologist when the Paleogene period started and odds are very good the answer will be about 65.5 million years ago.Ask about the Carboniferous and you’ll likely hear 359 million years ago.In 1654, the Archbishop James Ussher of Ireland calculated the age of all the Biblical generations and reported that the Earth was 4004 years old.

Since the formation of Earth, several geological changes have occurred, accompanied by the emergence of life and the process of evolution. Early calculations by William Thomson placed the age of the Earth to at most 400 million years old.

He argued that the Earth was formed as a molten object, and estimated the period it would take for the object to cool to the present temperature.

Before modern science, the age of the Earth remained virtually unknown.

In 1862, the physicist Lord Kelvin published the first thorough calculations, placing the planet’s age anywhere between 20 million and 400 million years.

Ask how old Earth is and the answer will almost invariably be 4.55 billion years, give or take a few tens of millions of years.

Today, most geologic ages are well established and widely agreed upon.People have been trying to estimate the age of the Earth for thousands of years.All mythologies have their own creation myths, while some Ancient thinkers like Aristotle thought our planet was eternal.Lord Kelvin and Clarence King calculated the length of time required for the Earth to cool from a white-hot liquid state; they eventually settled on 24 million years.James Joly calculated that the Earth’s age was 89 million years on the basis of the time required for salt to accumulate in the oceans.Bishop James Ussher, a 17th-century Irish cleric, for example, calculated that creation occurred in 4004 B. There were many other such estimates, but they invariably resulted in an Earth only a few thousand years old.