This shimmering cosmic curtain shows interstellar gas and dust that was heated by a supernova flash explosion long ago. The gas then emits infrared light in what is called a thermal light echo. As the supernova’s illumination travels through space at the speed of light, the echo appears to expand. NASA’s James Webb Space Telescope observed this bright echo near the remnant of the Cassiopeia A supernova.
Credits: NASA, ESA, CSA, STScI, J. Jencson (Caltech/IPAC)
