Energy-efficient diesel engines are nearly as green as hybrids, thanks to improved technology, exhaust scrubbers, and a new fuel. This article from the March 2007 edition of Scientific American explains.
If you recall the Nautilus, Captain Nemo's submarine in 20,000 Leagues Under the Sea, it was a very fast moving vessel. But we all know that water puts a huge drag on subs: in reality, high speed isn't possible underwater. Until now. New research is propelling secret torpedoes and other naval systems at hundreds of miles per hour. Steven Ashley reports in this article, which originally appeared in the May 2001 issue of Scientific American.