Dissipating gases such as carbon dioxide or sulfur dioxide reach the open air through fissures and pores. Scientists can collect gases directly from holes called fumaroles, but more often they use remote gas-identifying spectrometers. Warning time: days to weeks
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.