If the planet were shrunk down to a 2” diameter it would be more perfect and smooth than any man made ball bearing. Even with the Marianas trench and Mt Everest and K-2
And if that ball were dry, you could make deeper oceans just by breathing on it.
It’s the, “If the earth were the size of a billiard ball...” analogy. I first heard that in high school in the early ‘60s. It impressed me enough that it stuck in my head.
Did you say "ball bearing" ?