 Here, we have a visible light-hubble image of the remnants of a supernova called Cassiopeia A, 11,000 light-years away. We covered it in our How Far Away Is It segment on star clusters in supernova. It has been expanding for just 340 years and spans about 10 light-years. Here's a 2023 image from Webb's near-infrared camera. The most noticeable colors are clumps of bright orange and light pink that make up the inner shell of the supernova remnant. These knots of gas are composed of sulfur, oxygen, argon, and neon from the exploded star itself. Here's a new 2023 mid-infrared image from Webb. The striking colors hold a wealth of scientific information that researchers are just beginning to understand. From the bubble's exterior, particularly at the top and left, we see curtains of material appearing orange and red that are due to emissions from warm dust that's marking where ejected material from the exploded star is colliding into surrounding gas and dust. Interior to this outer shell there are filaments of bright pink studded with clumps and knots. A loop, represented in green, extends across the right side of the central cavity. Scientists do not yet understand how its shape and complexity came to be.