This is so disturbing. Like other times where this kind of thing has happened in the past, it will probably cause an exodus of scientists (at least, the few that CAN escape) that will benefit other countries and cause a loss in scientific power in Russia in the next generation.
It would! It is speculated that the supernova would be at its brightest for several weeks to a few months. It would appear as a star with the brightness of the Moon concentrated into a single point. We would see it during the day for several months to a year afterwards and we’d see it at night for a few years afterwards until it faded.