A Galaxy That Slept for Half a Billion Years ⚡ экспресс
Astronomers using the James Webb Space Telescope have found an unusual galaxy at a distance corresponding to when the universe was only about 1 billion years old. Dubbed 'Hibernating', it experienced a furious burst of star formation in the first 300 million years, and then went dormant for hundreds of millions of years. This led to a record Balmer break (a sharp jump in the spectrum) – 3 times stronger than any other galaxy from that epoch. Such objects appear to be more common than simulations predicted, and they challenge the idea that all bright early galaxies grow into massive systems: some, like 'Hibernating', may turn into faint dwarfs over time.
The James Webb Space Telescope looked back to a time when the universe, just after the Big Bang, was only a billion years old, and found the 'Sleepy' galaxy. Unlike its neighbors, which shone with young stars, it looked tired and dim.
Splitting light into its colors, scientists realized: in its first 300 million years, Sleepy blazed to life, piling up a mountain of stars, and then fell asleep for half a billion years. This slumber left a mark—a hydrogen dip in the glow, a sharp cutoff in the spectrum. It turned out to be three times stronger than in any other galaxy of that era, like the echo of a suddenly cut-off scream.
The discovery flips the script. Previously, it was thought that bright early galaxies inevitably grow into giants. Sleepy, instead, became a dim dwarf—and perhaps the majority of these 'expectation-defying' sleeping beauties exist.
🎯 By today, Sleepy would have become so dim that no modern telescope could see it—half a billion years of slumber have made it nearly invisible.