Around 1640, Bishop James Ussher, using traditional ages and dates found in the Old Testament, calculated that the world began at noon on October 23, 4004 BC.
In calculating that the world was created in 4004 BC, James Ussher was merely repeating a view widely held before his time, but with rather greater precision.
William Shakespeare, who died in 1616, reflected this view when he wrote in 'As You Like It', the line: "The poor world is almost six thousand years old . . ."
Jean-Baptiste Fourier argued that the earth's central heat was clearly revealed in higher temperatures observed deep in mines and by volcanic activity.
Fourier explained the earth's observed central heat by assuming the whole earth was once hot, and that the temperature of the earth was now falling.
In 1830, Charles Lyell began to publish his Principles of geology. In this, he proposed the revolutionary argument that the Earth is several million years old.
In 1846, William Thomson (Lord Kelvin ) wrongly estimated the Earth to be 100 million years old, based on heat calculations, assuming no internal heat source.
In 1862, Lord Kelvin estimated the age of the Earth, from its cooling time to be between 20 and 400 million years. Again, he assumed no internal heat sources.
In 1892, Sir Robert Ball gave the world about four or five million years more to go before it ended when the Sun used up all its energy, after 18 million years.
In 1903, George Darwin and John Joly suggested that radioactivity might warm the Earth, making the earth potentially much older than previously thought.
In 1904, Ernest Rutherford suggested the age of Earth might be longer than previously assumed on cooling estimates, due to internal heating by radioactivity.
In 1907, Bertram Borden Boltwood first proposed the use of radioactivity to date minerals, and offered dates for some rocks of 410 - 2200 million years.
By 1931, on the basis of assorted radioactivity and geological data, the age of the earth was now considered to be at least two billion years.
In 1954, a revised estimate, based on the best information, put the earth at 5 to 6 billion years, while estimates these days are more like 4.5 billion years.