Since the Viking Mars probes traveled to the red planet back in 1976, NASA has sent several more probes, landers, and rovers to the Martian surface to study the planet’s geology and search for signs of microbial life. But the evidence for life may have been hidden in Viking’s data all along. A new analysis of the data collected by probes Viking 1 and Viking 2 suggest the missions found evidence of microbial life more than three decades ago.
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.