Strange things are probably happening to the water deep inside Neptune and Uranus. The ultrahigh temperatures and pressures may be forcing it into new phases beyond the standard solid, liquid, and gas. Since we can't visit those planets to figure out what's really going on, an international team of researchers plans to create similar conditions here on Earth. First, they'll seal water into a compressor made of tantalum or tungsten. Then, they'll fire beams of heavy ions such as uranium at the container until the water within is sweltering under temperatures thousands of degrees Kelvin and pressures of several million atmospheres. These extremes may reveal two phases of water not commonly found on Earth: plasma, a high-energy state in the sun where the electrons aren't tied to any atom in particular and move about freely; and the superionic phase, an elusive state where the oxygen atoms form a solid crystal lattice and the hydrogen ions zip around and through it. A computer simulation published  today in New Journal of Physics shows that the experiment could work. But it's going to cost more than $1 billion and require 16 countries to foot the bill. Maybe visiting those planets isn't such a bad idea after all.
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