Ask a Physicist: Gild the Moon

Dr. Madhav Pakare from Mumbai wants to know: How much gold would it take to cover the moon in a layer one atom thick?Gold has been renowned for its malleability since ancient times and, while we've yet to create graphene-like structures that are a single atom thick, you can come close with tools no more complex than a hammer and some parchment; it's possible to expand a gold nugget to 20,000 times its initial surface area, creating sheets less than a thousandth of a millimeter in width. Right no...