The Earth began with a significant amount of internal heat, which has taken an extensive period to dissipate. This is similar to how rocks in a campfire can retain heat long after the fire has extinguished, illustrating that larger masses, like the Earth itself, are capable of holding heat for an extraordinarily long time, often in the order of billions of years.

This principle highlights the slow cooling process of rocky planets and emphasizes the geological timescales involved in Earth's development. It underlines the fascinating dynamics of our planet's history, where remnants of that initial heat continue to influence its geology and internal processes even today.