a very bright green space filled with stars

Crab Nebula Caption: The eerie glow of a dead star, which exploded long ago as a supernova, reveals itself in this NASA Hubble Space Telescope image of the Crab Nebula. But don't be fooled. The ghoulish-looking object still has a pulse. Buried at its center is the star's tell-tale heart, which beats with rhythmic precision. Credits: NASA and ESA; Acknowledgment: M. Weisskopf (NASA Marshall Space Flight Center)