James Webb Space Telescope Feed Post

NASA’s Webb Reveals Intricate Layers of Interstellar Dust, Gas

Webb is giving astronomers an unprecedented look of 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.” 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 average Earth-Sun distance and is equal to 93 million miles or 150 million kilometers.) Webb observed this light echo in the vicinity of the supernova remnant Cassiopeia A three separate times, in essence creating a 3D scan of the interstellar material. Note that the field of view in the top row is rotated slightly clockwise relative to the middle and bottom rows, due to the roll angle of the Webb telescope when the observations were taken. Read more: science.nasa.gov/missions/webb/nasas-webb-reveals-intrica... (Note: the black region of the image is where there is no data.) Credit: NASA, ESA, CSA, STScI, J. Jencson (Caltech/IPAC) Image description: Three rows show Webb images of the same region taken on three different dates. The top row is labeled August 19, 2024. The middle row is labeled September 16, 2024. The bottom row is labeled September 30, 2024. Each row shows two images split by a vertical black bar where there is no data. Each image is speckled with dozens of white stars, some showing Webb’s signature 8-point diffraction spikes, against the black background of space. The images also show tightly packed, glowing red filaments that resemble muscle fibers or wood grain. While the background stars are the same in every row, the filaments change noticeably. In the top row, the filaments extend horizontally from upper left to lower right. In the middle and bottom rows, the filaments extend from lower left to upper right, and seem to shift slightly downward in position, with the last the lowest. Image & Description by NASA