"Technologically speaking, China was so far ahead of the rest of Eurasia that foreign lands had little to offer except raw materials, which could be obtained without going to the bother of dispatching gigantic flotillas on lengthy journeys. Beijing easily could have sent Zheng past Africa to Europe, observed the George Mason University political scientist Jack Goldstone. But the empire stopped long-range exploration "for the same reason the United States stopped sending men to the moon--there was nothing there to justify the costs of such voyages."