Cuius est solum, eius est usque ad coelum et ad inferos, goes the axiom. Property rights extend not just to the surface, but infinitely out to space. This set us to thinking about a Robert Heinlein novella, The Man Who Sold the Moon. If we could somehow arrange to be directly under the Moon, we’d have ownership thereof. But the Moon is big. Really big. 3475 km in diameter. We’d need to own a piece of land about two-thirds the length of the US in order to claim the Moon.
…but wait a second. The Earth being round, our property wouldn’t be a column, but rather a cone, with the vertex at the center of the Earth and expanding as we ascend. Knowing the diameter of the Earth (7918 km) and the distance to the Moon (384,400 km), we can figure out what smaller piece of terrestrial property, located directly under the Moon’s orbit, would project a large enough cone to fully encompass the lunar disc. A little quick math and we come up with a circular plot of land a bit under 72km in diameter, or a little over 44 miles.
Anybody have some land for sale in Texas?
(For the record, yes, we know the doctrine is no longer still good. It started to die about the time man started to fly; if it were still good law, we could sue for trespass any passing aircraft.)