Even as a star dies, its light endures—echoing across the cosmos.⁣ ⁣ The James Webb Space Telescope is giving astronomers an unprecedented look at the fine details and 3D structure of the dust and gas between the stars.⁣ ⁣ The space between the stars is not empty, but rather filled with filaments of dust and gas (known as the interstellar medium), which is often invisible until something illuminates it.⁣ ⁣ Here, a long-ago supernova explosion, acting like a flashbulb, has heated some of this interstellar material, causing it to glow in the infrared, creating a thermal “light echo.”⁣ ⁣ As the supernova illumination travels through space at the speed of light, the echo appears to expand. Click the link in NASAWebb’s bio to read more and to see more images and a video showing the change over time.⁣ ⁣ The structures in these filaments are on a remarkably small scale of about 400 astronomical units, or less than one-hundredth of a light-year. (An astronomical unit, or AU, is the averag...