The "air bubble" theory that would allow a submarine to move through the ocean at supersonic speed could be closer to reality through the work of Chinese scientists. Called "supercavitating," the theory is being developed into new technology by scientists at the Harbin Institute of Technology's Complex Flow and Heat Transfer Lab, according to the South China Morning Post, and it could allow a submarine to reach supersonic speed underwater. The "air bubble" technology would allow a submarine to travel from Shanghai to San Francisco in less than two hours, if the technology can actually be pulled off, according to...