In chapter 25 of How Many Licks, Aaron Santos estimates how long will it take before the United States shares a border with China?
While much of the talk in Washington today concerns sealing up the border between the United States and Mexico to deter illegal immigration, in the future we may be talking about sealing up the American-Chinese border. Due to continental drift, the Atlantic Ocean gets about 2 cm (~0.8 in) wider every year. Consequently, the Pacific Ocean gets 2 cm (~0.8 in) smaller ever year. How long will it be until the United States and China share a border?
1) 500 million years
2) 1 billion years
3) 5 billion years
[Helpful Hint: Looking at a map, you can see that the Pacific Ocean is about 10,000 km = 1.0 x 10 (to the 9) cm (~6300 mi) wide.]