Q. Do you have an explanation for where the extra mass to increase the size of the Earth is coming from?
A. Yes. Cosmic material regularly adds extra mass to the Earth as yearly ‘cosmic showers’. But over geological time we know there are ‘cosmic storms’ that must add vast amounts of new material. This cosmic material is transported by geological processes that we observe today (erosion, sediment transport and subduction), into the interior of the Earth where it separates out into lighter and heavier elements. Chapter 5 of my book describes the evidence for this in greater detail.