2023-07-22 13:33:15
The dusty galaxy is in an area called GOODS-South that has been observed by the James Webb Space Telescope for many days. Image: ESA/Webb, NASA, ESA, CSA, B. Robertson (UC Santa Cruz), B. Johnson (Center for Astrophysics, Harvard & Smithsonian), S. Tacchella (University of Cambridge, M. Rieke (Univ. of Arizona), D. Eisenstein (Center for Astrophysics, Harvard & Smithsonian), A. Pagan (STScI)
The James Webb Space Telescope has once again made a surprising discovery: in a young galaxy almost a billion after the Big Bang, it discovered dust whose formation raises questions.
The universe is exceedingly dusty. Astronomers have known this for a long time, because the dust that, together with traces of gas, fills the space between the stars has blocked their view in some places for a long time. If you look up at the band of the Milky Way in a dark place, you can also see this phenomenon with the naked eye: the dark spots that shade the light of the stars of our home galaxy are such dusty clouds, inside which young stars are in turn forming.
Sibylle Anderl
Editor in the feuilleton, responsible for the “Nature and Science” department.
The starlight that the dust catches simultaneously heats it up and it begins to glow itself. Similarly, observing our galaxy with radio telescopes shows how the dust clouds themselves become sources of long-wave radiation. The way the dust absorbs starlight and how it itself emits radiation provide clues to its chemical composition. Broadly speaking, there are two types of particles, which can be up to a few microns in size: those containing carbon and those containing silicon. In dense clouds, they are often surrounded by ice mantles. These particles bind a large part of the heavy elements of the interstellar medium and thus decisively determine its chemistry.
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