NASA's James Webb Space Telescope has spotted a young galaxy dating to the early universe - called Firefly Sparkle because its gleaming star clusters resemble the bioluminescent bugs - in a discovery that is giving astronomers a peek at what our Milky Way may have looked like in its infancy.Researchers said the galaxy, still in the process of assembling, dates to when the universe was roughly 5% of its current age, about 600 million years after the Big Bang event that initiated the cosmos. It has a mass equal to about 10 million stars the size of our sun, and has two other relatively small galaxies as neighbors, dubbed Firefly-Best Friend and Firefly-New Best Friend.It is comprised of 10 densely packed star clusters embedded in a diffuse arc of stars, eight in its central region and two along its extended arm. Its main visible portion spans about 1,000 light-years across. A light year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km).The galaxy is estimated to have formed 100-400 million years before its evolutionary stage that was observed by Webb, the most capable space telescope ever deployed."The Milky Way began forming very early in the universe's history, likely around the same time as Firefly Sparkle," said astronomer Lamiya Mowla of Wellesley College in Massachusetts and the Center for Astronomy, Space Science and Astrophysics in Bangladesh, co-lead author of the study published on Wednesday in the journal Nature."This observation gives us a direct look at what galaxies like our Milky Way might have looked like in their infancy. Using simulations and statistical methods, we find that the Firefly Sparkle's mass is consistent with what we'd expect for a Milky Way ancestor at that early time. At this stage, the galaxy was about 10,000 times less massive than our current Milky Way, which is typical of galaxies at that epoch," Mowla added.So how did the firefly name come about?"A group of fireflies - which is what this galaxy looks like - is called a sparkle," Mowla said.Firefly Sparkle is located about 6,500 light-years from Firefly-Best Friend and about 42,000 light-years from Firefly-New Best Friend. All three would fit neatly inside the present-day Milky Way, which measures about 100,000 light-years across."The Milky Way continued to grow and evolve over billions of years through mergers with other galaxies and continued star formation, while we're seeing Firefly Sparkle in its initial formation stages," said astronomer and study co-lead author Kartheik Iyer, a NASA Hubble Fellow at Columbia University in New York.
