This star cluster, NGC 1910, contains one of the brightest known stars in the universe. Much studied, S Doradus is a luminous blue variable (LBV), a supermassive star that changes brightness dramatically over several years. At its brightest S Doradus was over a million times brighter than our Sun. Astronomers have found similar LBVs in other galaxies and have used them as a yardstick to help calculate the distance to these more distant galaxies.
