Do neutron star binary systems come from previously active-star binaries, where where both stars have gone supernova and left behind neutron stars that are still in orbit? Or do they form when two previously unbound neutron stars approach each other and fall into orbit?

This question has been puzzling me lately. I'm sure you've seen demonstrations of metal containers imploding when evacuated. Here, for example, are two videos of vacuum collapse: Experiment 1, starts at 1:58, Experiment 2 However, when the same experiment is conducted with a material as fragile...

I am not a physicist but I have been wondering about this: I understand that the decay of a nucleus is a random event and one cannot predict exactly when it will happen for a particular nucleus. What I would like to know is what triggers this event to happen?

J005311 is two white dwarf stars that have merged in such a way, that, well they merged instead of exploding. (Only 7 or so such mergers have been found.) Its stellar wind is blowing at 16,000 km per second and has reached a surface temperature of 200,000 C. The weird thing is it emits no ligh...