Their values were consistent with Thomson's calculations.
However, they assumed that the Sun was only glowing from the heat of its gravitational contraction.
In 1895 John Perry challenged Kelvin's figure on the basis of his assumptions on conductivity, and Oliver Heaviside entered the dialogue, considering it "a vehicle to display the ability of his operator method to solve problems of astonishing complexity." Other scientists backed up Thomson's figures. Darwin, proposed that Earth and Moon had broken apart in their early days when they were both molten.Other naturalists used these hypotheses to construct a history of Earth, though their timelines were inexact as they did not know how long it took to lay down stratigraphic layers.In 1830, geologist Charles Lyell, developing ideas found in James Hutton's works, popularized the concept that the features of Earth were in perpetual change, eroding and reforming continuously, and the rate of this change was roughly constant.He calculated the amount of time it would have taken for tidal friction to give Earth its current 24-hour day.His value of 56 million years added additional evidence that Thomson was on the right track.