Imagine being able to travel from Shanghai to San Francisco in less than two hours--underwater. Chinese researchers are working on creating submarines that harness something called supercavitation in order to achieve amazing speeds. Supercavitation technology has been around for decades and was used during the Cold War by the Soviet Union. While the Soviets didn't create a supersonic submarine, they did manage to produce a torpedo that could travel speeds near 230 miles per hour. 

According to the Register, supercavitation is when a subarine vessel creates a bubble of gas around itself while it moves through the water. This bubble reduces the amount of friction (or resistence) dramatically and allows for super speeds to be attained by supercavitating vessels. The way the bubble is created it by the vessel ejecting gases from the front of its frame, and the gases form a pocket around the vessel due to its motion. High speeds are a necessity though in order to maintain the bubble around the submarine. 

Researchers at the Harbin Institute of Technology's Complex Flow and Heat Transfer Lab have reportedly created a way to cover their supercavitating subs with a "liquid membrane" when they first launch; this is done to reduce friction or drag in the water long enough for the vessel to begin supercavitating. The membrane will wear off, but not before allowing the sub to create it's bubble and begin traveling at high speed. 

Harbin Institute scientists also claim to have created a way to steer their super sub design via manipulation of the liquid membrane. According to professor Li Fengchen of Harbin "By combining liquid-membrane technology with supercavitation, we can significantly reduce the launch challenges and make cruising control easier," he stated.

The goal is near supersonic speeds for their supercavitating submarines, a feat that would see these vessels traveling at around 767 miles per hour. Even though these vessels would significantly reduce friction to travel at such high speed, it would still require an enormous amount of energy to maintain high enough velocities to maintain the cavitation bubble.

And the application here is unclear. While mass transit under the world's oceans is intriguing, one can only imagine the environmental impact as we begin spewing expended rocket fuel into the sea. At the very least these subs are going to kill a lot of marine life.