Finally it happened. What happened? Even after the fact none of the observers knew; nor did any except the L3's ever find out. The fuses of all the recorder and analyzer circuits blew at once. Needles jumped instantly to maximum and wrapped themselves around their stops. Charts and ultraphotographic films showed only straight or curved lines running from the origin to and through the limits in zero time. Ploor and everything around it disappeared in an utterly indescribable and completely incomprehensible blast of pure, wild, raw, uncontrolled and uncontrollable energy. The infinitesimal fraction of that energy which was visible, heterodyned upon the ultra as it was and screened as it was, blazed so savagely upon the plates that it seared the eyes. And if the events caused by the planet aimed at Ploor were indescribable, what can be said of those initiated by the one directed against Ploor's sun? When the heat generated in the interior of a sun becomes greater than its effective surface is able to radiate, that surface expands. If the expansion is not fast enough, a more or less insignificant amount of the sun's material explodes, thus enlarging by force the radiant surface to whatever extent is necessary to restore equilibrium. Thus come into being the ordinary novae; suns which may for a few days or for a few weeks radiate energy at a rate a few hundreds of thousands of times greater than normal. Since ordinary novae can be produced at will by the collision of a planet with a sun, the scientists of the Patrol had long since completed their studies of all the phenomena involved. The mechanisms of supernovae, however, remained obscure. No adequate instrumentation had been developed to study conclusively the occasional supernova which occurred naturally. No supernova had ever been produced artificially--with all its resources of mass, atomic energy, cosmic energy, and sunbeams. Civilization could neither assemble nor concentrate enough power. At the impact of the second loose planet, accompanied by the excess energy of its impossible and unattainable intrinsic velocity, Ploor's sun became a supernova. How deeply the intruding thing penetrated, how much of the sun's mass exploded, never was and perhaps never will be determined. The violence of the explosion was such, however, that Klovian astronomers reported--a few years later--that it was radiating energy at the rate of some five hundred and fifty million suns. Thus no attempt will be made to describe what happened when the planet from nth space struck the Boskonians' sun. It was indescribably cubed. XXVII. The Boskonian fleets defending Ploor were not all destroyed, of course. The vessels were inertialess. None of the phenomena accompanying the coming into being of the supernova were propagated at a velocity above that of light; a speed which to any spaceship is scarcely a crawl.