Images from James Webb captured the unexpectedly bright glow of the first galaxies. A toaster browns a slice in a minute, while an oven bakes a loaf in an hour — the result is the same. So it is in space: young galaxies put out powerful light quickly, like a toaster, rather than baking stars slowly, like an oven.
The answer lies in the bursty birth rhythm. In the early universe, gas compressed into stars not continuously but in short bursts. Yet the fraction of gas turned into stars remained almost the same as today. The toaster used as much dough as the oven.
Neither cosmic dust nor giant stars alone could explain such brilliance — only the accelerated pace. A surprising twist: supermassive black holes at the centers of galaxies also played a part. As matter fell into them, it heated up and added light, making the baby galaxies even brighter.
The most distant known star cluster ignited when the universe was only 300–400 million years old, an infant age by cosmic standards.
In H.G. Wells's 'The Time Machine,' the distant future looks dim, but here the past is unexpectedly bright.