But So how exactly does Nasa know with this kind of certainty that T CrB is going to erupt above another handful of months specifically? It is a matter of mathematical calculations and visible proof. For example, the last time T CrB seasoned a nova was in 1946 – 78 https://checkbookmarks.com/story2832149/how-much-you-need-to-expect-you-ll-pay-for-a-good-nova-explosion-impact