Chandra Release - July 22, 2024 Visual Description: Supernova Remnant G21.5-0.9 This composite image depicts a supernova remnant, which has a bright nebula at its core, surrounded by a cloud of X-rays detected with Chandra. Here, the nebula is represented by a small golden yellow dot at the center of the image. The dot appears to hover inside a tangle of light blue veins, which resemble a lightning cluster. Enveloping the nebula is the massive x-ray cloud, which occupies much of the image. Round in shape, the diffuse X-ray cloud is shown here in mottled neon purple. It represents the debris from the star destroyed in the supernova explosion.