... Near the center of this sharp cosmic portrait, at the heart of the Orion Nebula, are four hot, massive stars known as the Trapezium. Gathered within a region about 1.5 light-years in radius, they dominate the core of the dense Orion Nebula Star Cluster. ... One night in mid-September near TromsЬ, Norway, high red aurora could be seen shimmering through lower green aurora in a way that created a striking and somewhat unusual violet glow. NGC 7293: The Helix Nebula . ... Stars in a Dusty Sky . ...