Under the program «Starfish» on July, 9th 1962 USA have blown up in space over Pacific ocean a hydrogen bomb with a trotyl equivalent 1.4 Mt. This event has put many questions before scientific community. Before it in 1957 the future Nobel winner doctor Hans Albrecht Bethe, being based on the theory of dipolar radiation, has foretold that at similar explosion the electromagnetic impulse (EMI) will be observed, thus intensity of a field on an earth surface will make no more than 100 В/м. Therefore all measuring equipment which should register electromagnetic radiation, has been adjusted on registration such intensity fields. But at bomb explosion it has appeared that intensity of electric fields, since explosion epicenter, and further throughout more than 1000 km has reached several tens thousand volt on meter. Those about past more than seventy years, but, until now, in the scientific journals be absent publication on the explanation of this phenomenon. This article gives the explanation of this phenomenon on the basis of the concept of scalar- vector potential, developed by the author. This concept assumes the dependence of the scalar potential of charge on its relative speed.