I WONDER - How Big Is The Planet Mercury?

Mercury is the smallest planet in the solar system, with a diameter of about 4880 kilometers, making it roughly three-quarters the length of the Amazon River. It is so small that 18 Mercurys could fit inside Earth, and it is only slightly larger than Earth's moon. Interestingly, Mercury is gradually shrinking due to the cooling of the planet, which causes its iron core to solidify.

What new insight or understanding did you gain from this video?