Hi, I was wondering whether or not there exists any neutronium on Earth. Could you not simply create neutronium by taking two neutrons and putting them together? If not, why not? I also heard that neutronium cannot exist outside the core of a neutron star... why? I'm assuming they mean that it won't exist because other particles (i.e. protons) would be attracted to the neutrons, so it would no longer be neutronium.