Engineers are constantly coming up with new ways to dispose of greenhouse gases. The latest idea is to hide carbon dioxide exhaust in cement. The method could revolutionize one of the most carbon-intensive industries in the world. Vinod Khosla has a lot of money, and he wants to put it to good use, which explains [...]

A UK-built solar-powered plane has set an unofficial world endurance record for a flight by an unmanned aircraft. The Zephyr-6, as it is known, stayed aloft for more than three days, running through the night on batteries it had recharged in sunlight. The flight was a demonstration for the US military, which is looking for [...]