Omomyid was among several readers writing in about the production of microscopic amounts of ultra-dense deuterium by scientists at the University of Gothenberg, in Sweden. A cubic centimeter of the stuff would weigh 287 lbs. (130 kg). UDD is 100,000 times more dense than water, and a million times more dense than deuterium ice, which is a common fuel in laser-ignited fusion projects. The researchers say that, if (big if) the material can be produced in large quantities, it would vastly improve the chances of starting a fusion reaction, as the atoms are much closer together. Such a D-D fusion reaction would be cleaner than one involving highly radioactive tritium. Many outlets have picked up the same press release that Science Daily printed pretty much verbatim (as is their wont); there doesn't seem to be much else about this on the Web. Here's the home page of one of the researchers. The press release gives no hint as to how the UDD was produced. Reader wisebabo asks: "I can easily imagine a material being compressed by some heavy duty diamond anvil to reach this density, the question is: what happens when you let the pressure off? Will it expand (explosively one would presume) back to its original volume?"