-----Original Message----- From: mix...@bigpond.com > Where they talk about endothermic reactions, they are talking about fusion of an element with itself, not with Hydrogen.
Not true. Cosmologists are talking about ALL possible nuclear reactions. There are many types of nucleosynthesis progressions in stars of different sizes. Some proceed in stages as you suggest but many others do not. Lots of hydrogen can be recaptured after an initial blow-off or when two paired stars are colliding over time. > This is because in stars, by the time the mid-level elements are formed, the Hydrogen *in the core* has long been consumed so there is none left to fuse with the other elements. That is one type of nucleosynthesis, but there are many other types that do not proceed that way. All nuclear fusion reactions that produce heavier elements than iron cause the star to lose energy and are said to be net endothermic reactions whether or not hydrogen is involved. > Because the binding energy is at a peak around Fe/Ni, any further fusion (e.g. Ni + Ni) would be endothermic. Yes, that much is true but only because all nuclear fusion reactions that produce heavier elements than iron cause the star to lose energy and are net endothermic reactions. > However fusion of *Hydrogen* with any of them would still be exothermic (as already shown here below). Not true unless you ignore the Coulomb barrier and the energy required to overcome it. The net energy of the reaction is based on much more than the final mass difference only. When the energy required to overcome the Coulomb barrier (even in the lower Gamow window) is factored into a final accounting, you will find a net loss of energy for fusion of elements heavier than iron in stars. > While the height of the Coulomb barrier plays a role in the likelihood that a fusion reaction between e.g. Ni & H will occur, such reactions are not energetically forbidden, i.e. they are exothermic, not endothermic. An endothermic reaction is never "forbidden" at all - and large levels of fusion can still operate at a net loss in stars as they cool rapidly. The individual reactants as *isolated entities* can have a mass difference on paper that appears exothermic, since no accounting exists for the other required factors that bring the reactants together, but hydrogen + nickel is not "net exothermic" on stars and there is no valid reason for Ni-H reactions to be "net exothermic" in condensed matter either, at least not as the fusion of charged particles. As we have opined before - the hydrogen atom (in deep electron orbital redundancy) being neutral, can possibly act as a "virtual neutron" in LENR. This is not proved, and is unlikely since no radioactive copper has been found, but without neutralizing Coulomb charge there is not net exotherm in Ni-H. Jones
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