Abstract only.During heavy-water electrochemical experiments in the 1980s, Fleischmann and Pons found that more thermal energy came out of their experiments with Pd cathodes than was put in electrically. The excess heat was greater than could be explained by any chemical reactions. Hence, they postulated that the excess energy was due to unexpected nuclear reactions. Now, it is well established experimentally that the amount of excess heat measured in many experiments greatly exceeds what can be attributed to chemistry. For this reason, and also because of numerous reports of nuclear reaction products and energetic radiations, it is widely believed that excess heat is due primarily, and maybe exclusively, to nuclear reactions. Hence, the field is now often called Low Energy Nuclear Reactions. There is an alternative scenario for production of excess heat and the observation of low levels of nuclear reaction products. It is far from new, but has received relatively little attention. Several theorists have postulated the formation of "compact objects" with sizes and energies between those of atoms and nuclei. If such objects do form, they could account for much of the measured excess heat. This paper is a review of the theories of compact objects and their implications
