Webb and Hubble sink deep into the dazzling Whirlpool Galaxy — Space photo of the week
Quick facts
What is this : A spiral arm of the Whirlpool Galaxy (M51)
Where it is: 31 million light years away in the constellation Canes Venatici
When it was shared: May 6, 2026
Stars form when vast clouds of dust and hydrogen gas collapse, creating a dense core that heats up until it becomes a nuclear fusion reactor. What happens moments after a star emerges from its birth cloud, however, remains a mystery.
This image of one of the spiral arms of the Whirlpool Galaxy (Messier 51) brings astronomers closer to solving this mystery and, in doing so, could answer a key question about the early universe.
Made by combining data from James Webb Space Telescope (JWST) and the Hubble Space TelescopeThe image shows that large groups of stars leave their birth clouds much faster than smaller ones. It is just one in a series extract from an article published on May 6 in the journal Natural astronomywhich reveals the processes that shape different galaxies.
As more stars are born in a collapsing cloud, strong stellar winds, intense ultraviolet light, and powerful explosions called supernovas begin to push out the surrounding gas. This process, called stellar feedback, prevents much of a galaxy’s gas from turning into new stars.
In this photo, red-orange threads of gas and dust stretch into lines, while blue bubbles illuminate certain areas of the interior. Gaps in the gas show clusters of bright white stars. (JWST’s ability to see infrared light has helped discover new stars that would be hidden behind dust with normal telescopes.)
Two zoomed and enlarged views of the Whirlpool Galaxy, seen by JWST and Hubble
(Image credit: ESA/Webb, NASA & CSA, A. Pedrini, A. Adamo (Stockholm University) and the FEAST JWST team)
Combined with the other images in the study, these images show a clear trend: The largest groups of stars dissipated their birth gas clouds in about 5 million years, while the smaller groups took between 7 and 8 million years to fully emerge. This has major implications for how galaxies evolve – and how the universe became hot again around 500 million to 1 billion years after the Big Bang.
Once the universe cooled, electrons and protons combined to form neutral atoms. Later, an unknown energy source separated them again during a period called reionization. Could this have been caused by intense ultraviolet radiation released into galaxies by massive star clusters?
“It must be the formation of massive star clusters that contributed to the reionization of the universe,” co-author of the study Daniela Calzetti from the University of Massachusetts at Amherst, said in a statement. “The fact that the most massive clusters could emerge from their natal clouds in just 5 million years means they had enough time to produce the photons that reionized the universe.”
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