Millis' math is actually more optimistic than other studies, which have suggested you would need 100 times the world's total energy output to cover that distance.
Police officers hold the line as they remove belongings left behind after they cleared Civic Center Park, on November 12, 2011. (AP Photo/Leah Millis - The Denver Post)
2011年11月12日，在清理了市中心公园以后，警察们移除了遗留物品之后仍然严防死守。
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"Someone's got to think beyond the obvious," says Marc Millis, a propulsion physicist at NASA's Glenn Research Center. "You have enough other people in the world doing the next obvious thing."