In a village forge, the blacksmith stokes the furnace, and sparks fly into the darkness. So too in the galaxy AEON-z5, an active nucleus, like a red-hot forge, ejects metal-enriched material far beyond the stellar disk. The James Webb Space Telescope captured this process just one billion years after the Big Bang, when the universe was still in its infancy.

The gas in the Hα+[N ii] line extends to a projected radius of more than 4 kiloparsecs, which is 2–2.5 times the effective radius of the stellar component, with a mass of about 2×$10^{10}$ solar masses. The central line profile can be decomposed into three components: a narrow core with a width of 88 km/s, a blue wing shifted by −288 km/s, and a dominant red asymmetric flow with a mean shift of +489 km/s and a width of 630 km/s. The high-velocity wing reaches 792 km/s, and a possible separate clump has a velocity of about 2800 km/s. It is as if not only sparks but also whole red-hot chunks of metal were flying out of the forge.

Previously, it was unclear whether active galactic nuclei could, within the first billion years after the Big Bang, eject metal-enriched gas to the outskirts of galaxies and into the surrounding medium. Now, the galaxy AEON-z5 has been found, where nitrogen and hydrogen emission is traced out to 4 kiloparsecs, and the gas metallicity is close to solar. This points to a real transfer of chemically processed material. We compared the spatial distribution of the emission lines with the size of the stellar disk and measured the gas velocities from the line shifts in the slitless spectrum. The result can serve as a benchmark for interpreting future observations of metal absorbers and for calibrating feedback models in the early universe. The sparks from the forge are spreading ever farther, and we are finally seeing them settle in the surrounding darkness, enriching it with metals for future generations of stars and planets.