Using a formula that astrophysicist Greg Laughlin had created, the planets have been given values in terms of currency. The Earth is valued at five quadrillion dollars, as of February 2011, making it the most expensive among 1,235 other planets.
Professor Laughlin used vital statistics such as each planet’s age, mass and temperature to come up with the formula. According to his calculations, Mars is only worth $14,000, while Venus is barely worth a cent. The reason for this is that these planets have inhospitable environments.
Despite the low price tags of other planets in space, purchasing them is not allowed because of a treaty established by the United Nations in 1967, the Outer Space Treaty. With a total of 102 state parties, this treaty forbids any nation from claiming territorial sovereignty over any part of outer space, including the moon and other celestial bodies.