Gerry Brown, together with other collaborators found that at high density another phenomenon happens, namely a condensation of K-minus Mesons, and K-minus mesons can condense and thereby lose their... thier normal mass so that their mass becomes smaller then... or let me say their MC² becomes smaller than the Fermi Energy of Electrons which would exist at the center of a neutron star. And so there is good reason to believe that when the density at the center of a... of as neutron star gets higher than, maybe, three, four times nuclear density, there is this K-minus condensation and the neutrons near the center again convert, not into protons plus electrons, but into protons plus K-minus mesons. And thereby the limiting mass of a neutron star is reduced from something like twice the mass of the sun to something like one-and-a-half times. And it is very believable from Jim Wilson's calculations, it is very believable that supernova 1987A had more than that mass and therefore would collapse to a black hole. As I said, not everybody believes this, but it is a very interesting theory, and it is very interesting how the very small varies the, and very high energy the K-minus mesons, how that connects again to astrophysics. This is, as I said, mostly the work of Gerry Brown and my only contribution was about the mass of the neutron star which first forms inside supernova 1987A.