When Betelgeuse finally collapses, the star – currently a red supergiant – will likely shine as brightly as the Moon in the sky for about two weeks, and be visible during the day time for 6-12 months after that. It will be a spectacular event, but calculating when it will happen is a tricky business. Every now and then in recent observations, Betelgeuse has grown dimmer or brightened, prompting speculation that the star may end up going supernova in a very short amount of time, measured in human lifespans or decades rather than astronomical timetables. It’s still unclear when the star will und…