NASA's James Webb discovers Firefly Sparkle galaxy with mass similar to the Milky Way

For the first time, astronomers using NASA’s James Webb Space Telescope have identified a galaxy, nicknamed the Firefly Sparkle, that not only is in the process of assembling and forming stars around 600 million years after the big bang, but also weighs about the same as our Milky Way galaxy if we could “wind back the clock” to weigh it as it developed. (Image: NASA)

For the first time, NASA's Webb Telescope "weighed" a galaxy. This galaxy existed 600 million years after the Big Bang. Remarkably, it shares mass traits with a young Milky Way. Named Firefly Sparkle, it glimmers with ten distinct star clusters.

Unique Insights from Firefly Sparkle Galaxy
Firefly Sparkle stands out among galaxies in its era. Most galaxies then were much larger, but this one isn’t. Scientists marvelled at its intricate star clusters and active formation. Researchers compared its sparkle to fireflies on summer nights.

This artist concept depicts a reconstruction of what the Firefly Sparkle galaxy looked like about 600 million years after the big bang if it wasn’t stretched and distorted by a natural effect known as gravitational lensing. (Image: NASA)

The galaxy’s discovery was aided by gravitational lensing effects. A massive foreground galaxy cluster magnified Firefly Sparkle’s appearance. Webb’s infrared imaging further clarified its structure and components.

Reconstruction Reveals Galaxy's Star Formation Process
Firefly Sparkle resembled an elongated raindrop in reconstructions. Within it, two clusters sat at the top, eight below. Diffuse light surrounded these clumps of star formation. Scientists noted its stars are still assembling, not fully formed.

Its stretched appearance allowed closer examination of its clusters. Each star group appeared in various star-forming phases. Observations confirmed staggered formation timelines across the galaxy's development.

Companions Could Shape Firefly Sparkle's Future
Two galaxies nearby orbit Firefly Sparkle in tight proximity. One lies 6,500 light-years away, the other 42,000. By comparison, the Milky Way spans 100,000 light-years. These companions may influence Firefly Sparkle’s growth and mass accumulation.

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Interactions between galaxies trigger cooling and star formation. Scientists believe these companions may merge with Firefly Sparkle. Such mergers reflect early universe galaxy-building theories in action.

This research was published in Nature on December 11, 2024.