Fusion, the same process that powers stars including the sun, would be a relatively clean, safe and near-limitless source of power. Unlike the fission of nuclear reactors that splits atoms to make energy, fusion fuses atoms. In nature, a star's immense gravity works to do the job of crushing hydrogen nuclei, protons, to create the reaction. But on Earth, crushing hydrogen atoms is no easy matter. It typically requires a machine that generates plasma -- atoms stripped of their electrons -- and runs at ultra-high temperatures in the millions of degrees Fahrenheit range. In short, more energy gets put in than what comes out, and that is not efficient.
But some scientists are trying to figure out how to get a fusion reaction to occur at room temperature. If successful, a so-called "cold fusion" machine would require little energy to run, but conversely produce a tremendous amount. In 1989, two scientists, Stanley Pons and Martin Fleischman, said they managed to achieve cold fusion, but after some initial excitement, the general consensus was that they didn't achieve cold fusion and in fact probably never would.
In the last couple of years, Italian inventor and entrepreneur, Andrea Rossi, claims he has achieved cold fusion with his "Energy Catalyzer," or "E-Cat" machine. The latest news is a supposedly independent test that validates his claims of a machine that somehow emits more energy (as heat) than it gets from the electrical outlets it is plugged into. A paper describing the test was posted on the ArXiv, a site where scientists post research before it goes for full peer-review.
Although Rossi staged demonstrations in 2011 attended by several journalists and a few scientists, he hasn't shared details about the machine or any of the data with other scientists nor has he allowed independent parties to confirm that a nuclear reaction has happened. In fact at one demonstration, he specifically disallowed a physicist from testing for the presence of gamma radiation. Despite the criticism, there are still supporters; among them Nobel laureate Brian Josephson, who pioneered superconductivity research.
Some types of nuclear reactions can theoretically occur at near-room temperatures, and there's a lot of active research into low energy nuclear reaction, or LENR. But that type of reaction isn't the same as cold fusion. "Cold fusion has no merit," said Steven B. Krivit
, publisher and senior editor, of the New Energy Times, who has covered LENR research for nearly a decade and authored books on the subject.
The difference, Krivit said, is that low-energy nuclear reactions operate according to known principles of physics, largely involving weak nuclear force interactions and capturing neutrons. While there is still a good deal of scientific controversy over LENR, the research exploring it doesn't invoke any new physics. Cold fusion requires that at least a few basic principles, such as the Standard Model, be wrong. So far no experiments have shown that they are.
Here are five reasons that cold fusion probably can't work, at least according to the laws of physics.