The 50% number is based on careful examination of rock age on the sea beds, which are all far younger than the rock above sea level on the islands and continents. The rock on the sea bed ages progressively in bands, with the older bands being near the continental coastlines, and the youngest near the center of the oceans. It's deduced that the planet was first composed only of the continents, which all fit together like a puzzle, but only on a sphere that is 50% smaller than the current earth. The extra surface area on the modern earth is all the ocean beds. In the past this has been incorrectly interpreted as "continental drift" - but they are not drifting, the surface area of the planet became greater, the origin points of new mass being the center of our current oceans, and moved them apart and away from each other. Here's good video summing up some of this, and there is also an excellent book:
I'm open to it being thousands of times larger, but that would bring its own set of problems.
I gotta ask, though:
Why would it expand? Due to the supposed expansion of the universe?
Could it observably expand over a few millennia?
What is this based on?
The 50% number is based on careful examination of rock age on the sea beds, which are all far younger than the rock above sea level on the islands and continents. The rock on the sea bed ages progressively in bands, with the older bands being near the continental coastlines, and the youngest near the center of the oceans. It's deduced that the planet was first composed only of the continents, which all fit together like a puzzle, but only on a sphere that is 50% smaller than the current earth. The extra surface area on the modern earth is all the ocean beds. In the past this has been incorrectly interpreted as "continental drift" - but they are not drifting, the surface area of the planet became greater, the origin points of new mass being the center of our current oceans, and moved them apart and away from each other. Here's good video summing up some of this, and there is also an excellent book:
https://www.youtube.com/watch?v=Othb0xsvZb4
https://www.expansiontectonics.com/wpPDF/ExpansionTectonicsHandout0915.pdf