Lord Kelvin calculated Earth was 20-400 million years old. Why was he wrong?
A) He didn't account for the erosion of sediments.
B) He didn't account for the presence of salt deposits.
C) He wrongly assumed the oceans were initially fresh.
D) His thermometer was incorrectly calibrated.
E) He didn't know Earth had an internal heat source.

Question

Quizplus · Accepted Answer

Lord Kelvin didn't know about the internal heat source of Earth, which was later discovered to be radioactive decay. This heat source had kept the Earth's core molten and led to the movement of tectonic plates, which he didn't take into account while calculating the age of the Earth.

Lord Kelvin Calculated Earth Was 20-400 Million Years Old