Another argument against the hypothesis is that if it were true, essentially all neutron stars should be made of strange matter, and otherwise none should be. Even if there were only a few strange stars initially, violent events such as collisions would soon create many fragments of strange matter flying around the universe. Because collision with a single strangelet would convert a neutron star to strange matter, all but a few of the most recently formed neutron stars should by now have already been converted to strange matter.