“Amazing, even for experienced astronomers”

“Amazing, even for experienced astronomers”

Spiral galaxies as seen by the James Webb Space Telescope.NASA image

Our Sun is also part of a spiral galaxy: the Milky Way. But because we are in the middle of it ourselves, it is difficult to map and study. Searching in other galaxies could help.

Because the Webb telescope observes infrared wavelengths (thermal radiation), it sees different things than a “normal” telescope. The (low) thermal radiation of microscopic dust particles is particularly striking – shown here in yellow, orange and red, depending on the exact wavelength.

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Govert Schilling is a science journalist specializing in astronomy. He has written dozens of books about the universe and, among other things, created the television series Government to the limits of the universe.

New stars

In addition to relatively cool dust, galaxies also contain large amounts of gas. New stars emerge from these clouds of gas and dust. Most young stars are found in the spiral arms of galaxies. The galactic core contains more ancient stars, which are colored blue in the Webb images.

The large, round, “empty” regions in the spiral arms of some galaxies are particularly striking. These “cavities” contain much less dust and gas. They were almost certainly destroyed by supernova explosions – massive stars that explode at the end of their short lives.

“Webb’s new images are stunning, even for astronomers who have been studying these types of galaxies for decades,” says study leader Janice Lee of the Space Telescope Science Institute in Baltimore.

How the spiral structure of galaxies is formed is still not well known. Spiral arms are a type of density waves in gas and dust, through which stars move — a bit like a long traffic jam on a highway, which isn't always made up of the same cars.

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