An unexpected cold wave in July 920 sent the people of Baghdad back under their blankets, forcing them to leave their summertime roof beds and go back inside, according to a new study by Spanish researchers. The temperature dropped about 16 degrees F compared to average July temperatures, the study found. That was in 920; there’s no “1” in there.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.