Hubble’s Extraordinary ULLYSES Program

The universe would be a pretty boring place without stars. Without them, the universe would remain a diffuse plasma of mostly hydrogen and helium from the big bang. To better understand stellar evolution, a new Hubble initiative has been launched called ULLYSES (UV Legacy Library of Young Stars as Essential Standards). This is the largest observing program ever undertaken by NASA’s Hubble Space Telescope, which will be used to look at over 300 stars. Ultraviolet (UV) light from the target stars will be