View original postIf we had 2 equally luminous suns? Yes absolutely. A couple of weeks of that would raise our temperature up a couple dozen degrees. But they really mean 'would be visible in the day time' and the human eye is logarithmic, a supernova would need to be a few light years away to match the suns brightness over the course of a couple of weeks. One aqs far away as Beetlegeuse will be only about as bright as the Full Moon, 1/10,000 as bright as the sun, maybe 10 times as much. It will be visible during the daytime and will be glorious at night if it's in the night sky when it happens, and it will be visible to the naked eye for some time thereafter, but its too far away to effect our temperature, it might at most in the initial day be bright enough that we'll be able to actually measure a temperature effect, but probably not much of one, a degree absolute tops.