Hey you're laughing at that now - but let's wait 5000 years into the future when man can walk on the sun, that deed will be worth billions if not trillions and trillions of dollars
Even if you are buying a deed now, it won't be worth anything 5,000 years later.
For example, take the case of Antarctica. During the 19th century, a lot of people "purchased" land on the south pole. What happened to them? They lost their money and got nothing in return when the UN declared that Antarctica doesn't belong to any nation or individual.