"The important thing is, one day, night will become day for several weeks on Earth." According to Wikipedia[1] the expected visible magnitude of the supernova

"The important thing is, one day, night will become day for several weeks on Earth." According to Wikipedia[1] the expected visible magnitude of the supernova is around -12mag. The full moon's apparent magnitude is around -12.74mag[2]. So we'd more likely have "another moon" for some time instead of a second sun. [1] http://en.wikipedia.org/wiki/Betelgeuse http://en.wikipedia.org/wiki/Betelgeuse [2] http://en.wikipedia.org/wiki/Apparent_magnitude http://en.wikipedia.org/wiki/Apparent_magnitude