Water is normally an excellent remedy for fires. But aboard the International Space Station, astronauts are investigating a novel form of water that actually starts fires. It's called "supercritical water", and it could revolutionise terrestrial rubbish disposal.
Here's how it works. When you compress a sample of water to 217 times its ambient atmospheric pressure and heat it to 373C, it goes supercritical and transforms into a liquid-gas plasma. In this state, any organic material that comes in contact with the water rapidly oxidises — essentially, burning without the flames.
Should we be able to harness this effect at the urban utility level, we'd have an easy means of incinerating waste without the side effect of heavy pollution — because without flames, the process doesn't actually create any harmful byproducts. The only downside is that the supercritical water generates a good deal of salt that, over time, can rust and corrode the system's piping. Still, it's a lot better than throwing a match on your trash in the backyard. [ScienceCasts via Pop Sci]