Robots run out of energy long before they run out of work to do. Feeding them could change that

Earlier this year, a robot completed a half-marathon in Beijing in just under 2 hours and 40 minutes. That's slower than the human winner, who clocked in at just over an hour—but it's still a remarkable feat. Many recreational runners would be proud of that time. The robot kept its pace for more than 13 miles (21 kilometers).